nix use overlays when convenient

21 files changed, 2633 insertions, 106 deletions

diff --git a/.envrc-local b/.envrc-local
new file mode 100644
index 0000000..bfa75d7
--- /dev/null
+++ b/.envrc-local
@@ -0,0 +1,16 @@
+if [[ ! -d ./.git ]]; then
+  git init
+  git add .
+fi
+echo '
+  .envrc-local echo ❯❯
+
+  ❯❯ nix flake update && nix flake check --show-trace && nix flake show && nix develop ".#devShell" -c zsh
+
+  ❯❯ nix develop
+  ❯❯ nix develop -c zsh
+  ❯❯ nix develop ".#dsh-overlay-ldc" --print-build-logs
+
+  ❯❯ nix build
+  ❯❯ nix build ".#default" --print-build-logs
+'
diff --git a/.gitignore b/.gitignore
index f7ece7f..9655923 100644
--- a/.gitignore
+++ b/.gitignore
@@ -10,9 +10,12 @@
 !*.nix
 !flake.lock
 !.envrc
+!.envrc-local
 !.envrc-nix
 !.env
 !.env/**
+!nix-overlays
+!nix-overlays/**
 !README.md
 !README
 !COPYRIGHT
diff --git a/flake.lock b/flake.lock
index a85e13f..4cf1693 100644
--- a/flake.lock
+++ b/flake.lock
@@ -5,11 +5,11 @@
         "systems": "systems"
       },
       "locked": {
-        "lastModified": 1681202837,
-        "narHash": "sha256-H+Rh19JDwRtpVPAWp64F+rlEtxUWBAQW28eAi3SRSzg=",
+        "lastModified": 1685518550,
+        "narHash": "sha256-o2d0KcvaXzTrPRIo0kOLV0/QXHhDQ5DTi+OxcjO8xqY=",
         "owner": "numtide",
         "repo": "flake-utils",
-        "rev": "cfacdce06f30d2b68473a46042957675eebb3401",
+        "rev": "a1720a10a6cfe8234c0e93907ffe81be440f4cef",
         "type": "github"
       },
       "original": {
@@ -20,11 +20,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1684973047,
-        "narHash": "sha256-ZLnSr35L6C49pCZS9fZCCqkIKNAeQzykov2QfosNG9w=",
+        "lastModified": 1685894048,
+        "narHash": "sha256-QKqv1QS+22k9oxncj1AnAxeqS5jGnQiUW3Jq3B+dI1w=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "21eb6c6ba74dcbe3ea5926ee46287300fb066630",
+        "rev": "2e56a850786211972d99d2bb39665a9b5a1801d6",
         "type": "github"
       },
       "original": {
diff --git a/flake.nix b/flake.nix
index 7e89065..4f487f0 100644
--- a/flake.nix
+++ b/flake.nix
@@ -19,6 +19,18 @@
       dub test --combined --skip-registry=all
       runHook postCheck
     '';
+    localOverlay = (final: prev: {
+      ldc = prev.callPackage ./nix-overlays/ldc {  };
+      dmd = prev.callPackage ./nix-overlays/dmd {  };
+      dub = prev.callPackage ./nix-overlays/dub {  };       # -> ?
+      #gdc = prev.callPackage ./nix-overlays/gdc {  };      # empty
+    });
+    pkgsForSystem = system: import nixpkgs {
+      overlays = [
+        localOverlay
+      ];
+      inherit system;
+    };
     installPhase = ''
       runHook preInstall
       mkdir -p $out/bin
@@ -31,9 +43,10 @@
     '';
   in {
     packages = forAllSystems (system: let
+      pkgs-ovl = pkgsForSystem system;
       pkgs = nixpkgsFor.${system};
     in
-      with pkgs; {
+      with pkgs-ovl; {
         default = stdenv.mkDerivation {
           inherit pname;
           inherit version;
@@ -53,7 +66,7 @@
             done
             if [ "$DC" == "" ]; then exit "Error: could not find D compiler"; fi
             echo "$DC_ used as D compiler to build $pname"
-            dub build --compiler=$DC --build=$DC_ --combined --skip-registry=all
+            dub build --cache=local --compiler=$DC --build=$DC_ --combined --skip-registry=all
             runHook postBuild
           '';
           inherit checkPhase;
@@ -72,7 +85,7 @@
           nativeBuildInputs = [dub dmd gnumake];
           buildPhase = ''
             runHook preBuild
-            dub build --compiler=$(type -P dmd) --build=dmd --combined --skip-registry=all
+            dub build --cache=local --compiler=$(type -P dmd) --build=dmd --combined --skip-registry=all
             runHook postBuild
           '';
           inherit checkPhase;
@@ -91,7 +104,7 @@
           nativeBuildInputs = [dub ldc gnumake];
           buildPhase = ''
             runHook preBuild
-            dub build --compiler=$(type -P ldc2) --build=ldc2 --combined --skip-registry=all
+            dub build --cache=local --compiler=$(type -P ldc2) --build=ldc2 --combined --skip-registry=all
             runHook postBuild
           '';
           inherit checkPhase;
@@ -110,7 +123,7 @@
         #  nativeBuildInputs = [ dub gdc gnumake ];
         #  buildPhase = ''
         #    runHook preBuild
-        #    dub build --compiler=$(type -P gdc) --build=gdc --combined --skip-registry=all
+        #    dub build --cache=local --compiler=$(type -P gdc) --build=gdc --combined --skip-registry=all
         #    runHook postBuild
         #  '';
         #  inherit checkPhase;
@@ -126,13 +139,14 @@
       };
     });
     devShells = forAllSystems (system: let
+      pkgs-ovl = pkgsForSystem system;
       pkgs = nixpkgsFor.${system};
       shellHook = ''
-        export DFLAGS="-O2 -inline -boundscheck=on -color=on"
+        export DFLAGS="-O2 -boundscheck=on"
         export Date=`date "+%Y%m%d"`
       '';
     in
-      with pkgs; {
+      with pkgs-ovl; {
         devShell = mkShell {
           name = "spine base dev shell";
           inherit shell;
@@ -141,9 +155,37 @@
           #nativeBuildInputs = [ dub dmd ldc gdc gnumake ];
           packages = [
             sqlite
-            dub
+            ldc
             #dmd
+            dub
+            gnumake
+          ];
+          inherit shellHook;
+        };
+        devShell-dmd = mkShell {
+          name = "spine base dev shell";
+          inherit shell;
+          inherit devEnv;
+          #buildInputs = [ sqlite ];
+          #nativeBuildInputs = [ dub dmd ldc gdc gnumake ];
+          packages = [
+            sqlite
+            dmd
+            dub
+            gnumake
+          ];
+          inherit shellHook;
+        };
+        devShell-ldc = mkShell {
+          name = "spine base dev shell";
+          inherit shell;
+          inherit devEnv;
+          #buildInputs = [ sqlite ];
+          #nativeBuildInputs = [ dub dmd ldc gdc gnumake ];
+          packages = [
+            sqlite
             ldc
+            dub
             gnumake
           ];
           inherit shellHook;
@@ -154,7 +196,7 @@
           inherit devEnv;
           packages = [
             dub
-            dmd
+            #dmd
             ldc
             gnumake
             sqlite
diff --git a/makefile b/makefile
index 423bfdc..3cbdc77 100644
--- a/makefile
+++ b/makefile
@@ -1,4 +1,4 @@
-include .envrc-local
+#include .envrc-local
 PROG_VER_GIT :=$(shell echo `git describe --long --tags | sed -e "s/^[ a-z_-]\+\([0-9.]\+\)/\1/;s/\([^-]*-g\)/r\1/;s/-/./g"`)
 PROG_VER_DECLARED :=$(shell echo `cat ./views/version.txt | grep --color=never "enum" | sed 's/.\+(\([0-9]\+\),[ \t]\+\([0-9]\+\),[ \t]\+\([0-9]\+\)[ \t]*).\+/\1.\2.\3/g'`)
 DUB=dub
@@ -431,44 +431,6 @@ spineWWWrsyncLinode:
 	rsync -v /var/www/sqlite/spine.search.db linode:./stage/. ; \
 	echo "tar -xf ../spine_output.$${Date}.tar.bz2"
 
-# get project external dependencies
-depends_get:
-	dub upgrade; \
-	cd $${gwd} && \
-	echo "$${dirs_loc}" && \
-	for dir in $${dirs_loc}; do \
-	  if [[ -d $${dir} ]]; then \
-	    echo $${gwd}/$${dir} && \
-	    if [[ "imageformats" == $${dir} ]]; then \
-	      echo $${gwd}/$${dir} && \
-	      rm -rvf $${gwd}/$${dir} && \
-	      git clone --depth=1 https://github.com/tjhann/$${dir} && \
-	      cd $${dir} && \
-	      echo $$PWD && \
-	      echo "$${dir} `git rev-parse HEAD | cut -c 1-8`"   > ../$${dir}.meta && \
-	      echo "https://github.com/tjhann/$${dir}"           >> ../$${dir}.meta && \
-	      echo "Boost Software License 1.0 (BSL-1.0)"       >> ../$${dir}.meta && \
-	      cd $${gwd} && \
-	      rm -rf $${gwd}/$${dir}/.git; \
-	    elif [[ "d2sqlite3" == $${dir}  || "D-YAML" == $${dir} || "tinyendian" == $${dir} ]]; then \
-	      echo $${gwd}/$${dir} && \
-	      rm -rvf $${gwd}/$${dir} && \
-	      git clone --depth=1 https://github.com/dlang-community/$${dir} && \
-	      cd $${gwd}/$${dir} && \
-	      echo "$${dir} `git rev-parse HEAD | cut -c 1-8`"   > ../$${dir}.meta && \
-	      echo "https://github.com/dlang-community/$${dir}"  >> ../$${dir}.meta && \
-	      echo "Boost Software License 1.0 (BSL-1.0)"       >> ../$${dir}.meta && \
-	      cd $${gwd} && \
-	      rm -rf $${gwd}/$${dir}/.git; \
-	    fi; \
-	  fi; \
-	done; \
-	cd $${hwd}
-
-# get and set project external dependencies
-depends_set: depends_get
-	dub describe | sed 's~$(shell echo `pwd | sed 's_/_\\/_g'`)~.~g'  > dub_describe.json
-
 changelog_:
 	git log --pretty=format:'---%+s %+as %ae%+h%d%+b' --no-merges | sed "/^\\s*$$/d" | sed "s/^---$$//" | sed "s/^\(\*\)\+/-/" | sed "s/ \+$$//" > CHANGELOG_
 
@@ -516,16 +478,19 @@ nixGitHEADtarballBuild:
 # clean create check & build test tarball
 nixGitHEADtarball: nixGitHEADtarballClean nixGitHEADtarballTar nixGitHEADtarballCheck nixGitHEADtarballBuild
 
+# get project external dependencies
 get_depends:
 	hwd=$$(echo `pwd`) && \
 	gwd="$${hwd}/src/ext_depends" && \
-	dirs=$$(echo `ls -gx $${gwd}`) && \
 	license_bsl="Boost Software License 1.0 (BSL-1.0)" && \
 	echo $${hwd} && \
 	echo $${gwd} && \
-	echo $${deps} && \
 	dub upgrade; \
+	if [ ! -d $${gwd} ]; then \
+	  mkdir -p $${gwd}/{d2sqlite3,D-YAML,imageformats,tinyendian}; \
+	fi; \
 	cd $${gwd} && \
+	deps=`ls -gx '.'` && \
 	for dir in $${deps}; do \
 	  if [ -d $${dir} ]; then \
 	    echo $${dir} && \
@@ -555,6 +520,7 @@ get_depends:
 	done; \
 	cd $${hwd}
 
+# get and set project external dependencies
 set_depends: get_depends
 	dub describe | sed 's~$(shell echo `pwd | sed 's_/_\\/_g'`)~.~g'  > dub_describe.json
 
diff --git a/nix-overlays/README b/nix-overlays/README
new file mode 100644
index 0000000..3e40ec0
--- /dev/null
+++ b/nix-overlays/README
@@ -0,0 +1,153 @@
+-*- mode: org -*-
+#+TITLE:       D related overlays
+#+DESCRIPTION: ldc, dub, dtools: dlang compiler build tool and tools
+#+FILETAGS:    :dlang:build:tools:
+#+AUTHOR:      Ralph Amissah
+#+EMAIL:       [[mailto:ralph.amissah@gmail.com][ralph.amissah@gmail.com]]
+#+COPYRIGHT:   Copyright (C) 2015 - 2023 Ralph Amissah
+#+LANGUAGE:    en
+#+STARTUP:     content hideblocks hidestars noindent entitiespretty
+#+OPTIONS:     H:3 num:nil toc:t \n:nil @:t ::t |:t ^:nil _:nil -:t f:t *:t <:t
+#+PROPERTY:    header-args  :exports code
+#+PROPERTY:    header-args+ :noweb yes
+#+PROPERTY:    header-args+ :eval no
+#+PROPERTY:    header-args+ :results no
+#+PROPERTY:    header-args+ :cache no
+#+PROPERTY:    header-args+ :padline no
+
+* README for D related overlays
+** dlang-nix-overlays
+
+Nix build overlays for building and testing more recent versions of the dlang
+compiler and build tools: ldc, dub and dtools, than exist in nixpkgs at the time
+of publishing, in some cases with additional fixes.
+
+nix overlays for (updates nixpkgs, more recent versions of):
+  - ldc     ( 1.30.0 -> 1.33.0-beta1 )
+  - dub     ( 1.23.0 -> 1.30.0 ) [for nix versions 1.31.0 ... 1.33.0 broken]
+  - dtools  ( 2.095.1 -> 2.103.1 )
+
+  - dmd     ( 2.100.2 -> 2.104.0 ) KO ✗
+  - gdc     [not yet available]
+
+(updates nixpkgs circa 2023-05-12)
+
+dlang-nix-flakes.org --❯
+  .
+  └── nix-overlays
+      ├── dmd
+      │   ├── binary.nix
+      │   ├── bootstrap.nix
+      │   ├── default.nix
+      │   └── generic.nix
+      ├── dtools
+      │   └── default.nix
+      ├── dub
+      │   └── default.nix
+      ├── ldc
+      │   ├── binary.nix
+      │   ├── bootstrap.nix
+      │   ├── default.nix
+      │   └── generic.nix
+      └── README
+
+search nixpkgs here:
+
+- https://search.nixos.org/packages?channel=unstable&from=0&size=100&sort=relevance&query=
+
+** compilers
+*** ldc OK ✓ ( 1.30.0 -> 1.33.0-beta1 )
+
+- https://wiki.dlang.org/LDC
+
+- https://github.com/ldc-developers/ldc
+  - https://github.com/ldc-developers/ldc/releases
+    nix-prefetch-url --unpack https://github.com/ldc-developers/ldc/archive/refs/tags/v1.33.0-beta1.tar.gz
+  - https://github.com/ldc-developers/ldc/issues
+
+- version in nixpkgs:
+  - https://search.nixos.org/packages?channel=unstable&show=ldc&from=0&size=100&sort=relevance&type=packages&query=ldc
+
+*** dmd KO ✗ ( 2.100.2 -> 2.104.0 )
+
+- https://dlang.org/
+  - https://wiki.dlang.org/LDC
+
+- https://github.com/dlang/dmd
+  - https://github.com/dlang/dmd/tags
+    nix-prefetch-url --unpack https://github.com/dlang/dmd/archive/refs/tags/v2.104.0.tar.gz
+  - https://github.com/dlang/dmd/pulls
+
+- version in nixpkgs:
+  - https://search.nixos.org/packages?channel=unstable&show=dmd&from=0&size=100&sort=relevance&type=packages&query=dmd
+
+- dmd nixpkg modified and appears to build ok, but it appears my overlay does
+  not get things right REVIEW
+
+- dmd on nixos FAILS to build (my working projects), appears not to find parts
+  of itself
+
+*** gdc ( not provided yet with gcc12 in nixpkgs )
+
+not yet provided in nixpkgs with gcc12, no attempt made
+
+- https://wiki.dlang.org/GDC
+  - https://wiki.dlang.org/GDC_Development
+
+- https://github.com/D-Programming-GDC/gdc
+
+** build tool
+*** dub ( 1.23.0 -> 1.30.0 )
+
+- https://code.dlang.org/packages/dub
+
+- https://github.com/dlang/dub
+  - https://github.com/dlang/dub/releases
+    nix-prefetch-url --unpack https://github.com/dlang/dub/archive/refs/tags/v1.30.0.tar.gz
+  - https://github.com/dlang/dub/issues
+
+- version in nixpkgs:
+  - https://search.nixos.org/packages?channel=unstable&show=dub&from=0&size=100&sort=relevance&type=packages&query=dub
+
+- dub nixpkg overlay is updated and runs most dub tests correctly
+
+- dub from v1.31.0 FAILS to build packages with nix tools that previous version
+  of dub built (from v1.23.0 to v1.30.0 which is currently in nixpkgs); FAILURE
+  is from v1.31.0 through v1.32.1 (which is current at the time of this commit)
+
+** tools
+*** dtools OK ✓ ( 2.095.1 -> 2.103.1 )
+
+- https://code.dlang.org/packages/dtools
+
+- https://github.com/dlang/tools
+  - https://github.com/dlang/tools/tags
+    nix-prefetch --unpack https://github.com/dlang/tools/archive/refs/tags/v2.103.1.tar.gz
+  - https://github.com/dlang/tools/issues
+
+- version in nixpkgs
+  - https://search.nixos.org/packages?channel=unstable&show=dtools&from=0&size=100&sort=relevance&type=packages&query=dtools
+
+** nixpkgs
+
+It is possible to work directly against a local copy of nixpkgs. To do so you
+would clone nixpkgs and point to the local nixpkgs as your build source.
+
+git clone --depth=1 --branch master https://github.com/nixos/nixpkgs nixpkgs
+
+- ./nixpkgs/pkgs/development/compilers/ldc
+- ./nixpkgs/pkgs/development/compilers/dmd
+- ./nixpkgs/pkgs/development/tools/build-managers/dub
+- ./nixpkgs/pkgs/development/tools/dtools
+
+- ./nixpkgs/pkgs/development/compilers/gcc
+
+Note the overlays if copied to the nixpkgs path locations should work as they do
+in the overlay, with a pointer to the cloned nixpkgs as nixpkgs repository
+source. In fact the starting point for the overlays was to take verbatim what
+was in nixpkgs and then to update and fix where necessary those packages.
+
+It is possible to compare the changes made by the overlays here directly against
+what is currently available in nixpkgs.
+
+- https://search.nixos.org/packages?channel=unstable&size=100&sort=relevance&query=
diff --git a/nix-overlays/dmd/binary.nix b/nix-overlays/dmd/binary.nix
new file mode 100644
index 0000000..6a99d42
--- /dev/null
+++ b/nix-overlays/dmd/binary.nix
@@ -0,0 +1,72 @@
+{ lib, stdenv, fetchurl, curl, tzdata, autoPatchelfHook, fixDarwinDylibNames, glibc
+, version, hashes }:
+
+let
+  inherit (stdenv) hostPlatform;
+  OS = if hostPlatform.isDarwin then "osx" else hostPlatform.parsed.kernel.name;
+  MODEL = toString hostPlatform.parsed.cpu.bits;
+in stdenv.mkDerivation {
+  pname = "dmd-bootstrap";
+  inherit version;
+
+  src = fetchurl rec {
+    name = "dmd.${version}.${OS}.tar.xz";
+    url = "http://downloads.dlang.org/releases/2.x/${version}/${name}";
+    sha256 = hashes.${OS} or (throw "missing bootstrap sha256 for OS ${OS}");
+  };
+
+  dontConfigure = true;
+  dontBuild = true;
+
+  nativeBuildInputs = lib.optionals hostPlatform.isLinux [
+    autoPatchelfHook
+  ] ++ lib.optionals hostPlatform.isDarwin [
+    fixDarwinDylibNames
+  ];
+  propagatedBuildInputs = [
+    curl
+    tzdata
+  ] ++ lib.optionals hostPlatform.isLinux [
+    glibc
+    stdenv.cc.cc.libgcc
+  ];
+
+  installPhase = ''
+    runHook preInstall
+
+    mkdir -p $out
+
+    # try to copy model-specific binaries into bin first
+    mv ${OS}/bin${MODEL} $out/bin || true
+
+    mv src license.txt ${OS}/* $out/
+
+    # move man into place
+    mkdir -p $out/share
+    mv man $out/share/
+
+    # move docs into place
+    mkdir -p $out/share/doc
+    mv html/d $out/share/doc/
+
+    # fix paths in dmd.conf (one level less)
+    substituteInPlace $out/bin/dmd.conf --replace "/../../" "/../"
+
+    runHook postInstall
+  '';
+
+  # Stripping on Darwin started to break libphobos2.a
+  # Undefined symbols for architecture x86_64:
+  #   "_rt_envvars_enabled", referenced from:
+  #       __D2rt6config16rt_envvarsOptionFNbNiAyaMDFNbNiQkZQnZQq in libphobos2.a(config_99a_6c3.o)
+  dontStrip = hostPlatform.isDarwin;
+
+  meta = with lib; {
+    description = "Digital Mars D Compiler Package";
+    # As of 2.075 all sources and binaries use the boost license
+    license = licenses.boost;
+    maintainers = [ maintainers.lionello ];
+    homepage = "https://dlang.org/";
+    platforms = [ "x86_64-darwin" "i686-linux" "x86_64-linux" ];
+  };
+}
diff --git a/nix-overlays/dmd/bootstrap.nix b/nix-overlays/dmd/bootstrap.nix
new file mode 100644
index 0000000..16aa5ed
--- /dev/null
+++ b/nix-overlays/dmd/bootstrap.nix
@@ -0,0 +1,9 @@
+{ callPackage }:
+callPackage ./binary.nix {
+  version = "2.090.1";
+  hashes = {
+    # Get these from `nix-prefetch-url http://downloads.dlang.org/releases/2.x/2.090.1/dmd.2.090.1.linux.tar.xz` etc..
+    osx = "sha256-9HwGVO/8jfZ6aTiDIUi8w4C4Ukry0uUS8ACP3Ig8dmU=";
+    linux = "sha256-ByCrIA4Nt7i9YT0L19VXIL1IqIp+iObcZux407amZu4=";
+  };
+}
diff --git a/nix-overlays/dmd/default.nix b/nix-overlays/dmd/default.nix
new file mode 100644
index 0000000..7beb9e5
--- /dev/null
+++ b/nix-overlays/dmd/default.nix
@@ -0,0 +1,6 @@
+import ./generic.nix {
+  version = "2.104.0";
+  dmdSha256 = "sha256-yv+uW6cYAId2HK/YSPxsR9Xt0o3LWa97z8KyzjFik6s=";
+  #druntimeSha256 = "";
+  phobosSha256 = "sha256-cWp36Gd/lh3gy21bf9z0/RqzlJmf6ypmx72aMeakcec=";
+}
diff --git a/nix-overlays/dmd/generic.nix b/nix-overlays/dmd/generic.nix
new file mode 100644
index 0000000..e500385
--- /dev/null
+++ b/nix-overlays/dmd/generic.nix
@@ -0,0 +1,219 @@
+{ version
+, dmdSha256
+, phobosSha256
+}:
+
+{ stdenv
+, lib
+, fetchFromGitHub
+, makeWrapper
+, which
+, writeTextFile
+, curl
+, tzdata
+, gdb
+, callPackage
+, targetPackages
+, fetchpatch
+, bash
+, installShellFiles
+, git
+, unzip
+, HOST_DMD ? "${callPackage ./bootstrap.nix { }}/bin/dmd"
+}:
+
+let
+  dmdConfFile = writeTextFile {
+    name = "dmd.conf";
+    text = (lib.generators.toINI { } {
+      Environment = {
+        DFLAGS = ''-I@out@/include/dmd -L-L@out@/lib -fPIC ${lib.optionalString (!targetPackages.stdenv.cc.isClang) "-L--export-dynamic"}'';
+      };
+    });
+  };
+
+  bits = builtins.toString stdenv.hostPlatform.parsed.cpu.bits;
+  osname =
+    if stdenv.isDarwin then
+      "osx"
+    else
+      stdenv.hostPlatform.parsed.kernel.name;
+
+  pathToDmd = "\${NIX_BUILD_TOP}/dmd/generated/${osname}/release/${bits}/dmd";
+in
+
+stdenv.mkDerivation rec {
+  pname = "dmd";
+  inherit version;
+
+  enableParallelBuilding = true;
+
+  srcs = [
+    (fetchFromGitHub {
+      owner = "dlang";
+      repo = "dmd";
+      rev = "v${version}";
+      sha256 = dmdSha256;
+      name = "dmd";
+    })
+    (fetchFromGitHub {
+      owner = "dlang";
+      repo = "phobos";
+      rev = "v${version}";
+      sha256 = phobosSha256;
+      name = "phobos";
+    })
+  ];
+
+  sourceRoot = ".";
+
+  # https://issues.dlang.org/show_bug.cgi?id=19553
+  hardeningDisable = [ "fortify" ];
+
+  #patches = lib.optionals (lib.versionOlder version "2.088.0") [
+  #  # Migrates D1-style operator overloads in DMD source, to allow building with
+  #  # a newer DMD
+  #  (fetchpatch {
+  #    url = "https://github.com/dlang/dmd/commit/c4d33e5eb46c123761ac501e8c52f33850483a8a.patch";
+  #    stripLen = 1;
+  #    extraPrefix = "dmd/";
+  #    sha256 = "sha256-N21mAPfaTo+zGCip4njejasraV5IsWVqlGR5eOdFZZE=";
+  #  })
+  #] ++ lib.optionals (lib.versionOlder version "2.092.2") [
+  #  # Fixes C++ tests that compiled on older C++ but not on the current one
+  #  (fetchpatch {
+  #    url = "https://github.com/dlang/druntime/commit/438990def7e377ca1f87b6d28246673bb38022ab.patch";
+  #    stripLen = 1;
+  #    extraPrefix = "druntime/";
+  #    sha256 = "sha256-/pPKK7ZK9E/mBrxm2MZyBNhYExE8p9jz8JqBdZSE6uY=";
+  #  })
+  #];
+
+  postPatch = ''
+    patchShebangs dmd/compiler/test/{runnable,fail_compilation,compilable,tools}{,/extra-files}/*.sh
+
+    rm dmd/compiler/test/runnable_cxx/cppa.d
+
+    # Grep'd string changed with gdb 12
+    #   https://issues.dlang.org/show_bug.cgi?id=23198
+    substituteInPlace dmd/druntime/test/exceptions/Makefile \
+      --replace 'in D main (' 'in _Dmain ('
+
+    # We're using gnused on all platforms
+    substituteInPlace dmd/druntime/test/coverage/Makefile \
+      --replace 'freebsd osx' 'none'
+  ''
+
+  + lib.optionalString (lib.versionOlder version "2.091.0") ''
+    # This one has tested against a hardcoded year, then against a current year on
+    # and off again. It just isn't worth it to patch all the historical versions
+    # of it, so just remove it until the most recent change.
+    rm dmd/compiler/test/compilable/ddocYear.d
+  '' + lib.optionalString (lib.versionAtLeast version "2.089.0" && lib.versionOlder version "2.092.2") ''
+    rm dmd/compiler/test/dshell/test6952.d
+  '' + lib.optionalString (lib.versionAtLeast version "2.092.2") ''
+    substituteInPlace dmd/compiler/test/dshell/test6952.d --replace "/usr/bin/env bash" "${bash}/bin/bash"
+  ''
+
+  + lib.optionalString stdenv.isLinux ''
+    substituteInPlace phobos/std/socket.d --replace "assert(ih.addrList[0] == 0x7F_00_00_01);" ""
+  '' + lib.optionalString stdenv.isDarwin ''
+    substituteInPlace phobos/std/socket.d --replace "foreach (name; names)" "names = []; foreach (name; names)"
+  '';
+
+  nativeBuildInputs = [
+    makeWrapper
+    which
+    installShellFiles
+  ] ++ lib.optionals (lib.versionOlder version "2.088.0") [
+    git
+  ];
+
+  buildInputs = [
+    curl
+    tzdata
+  ];
+
+  nativeCheckInputs = [
+    gdb
+  ] ++ lib.optionals (lib.versionOlder version "2.089.0") [
+    unzip
+  ];
+
+  buildFlags = [
+    "BUILD=release"
+    "ENABLE_RELEASE=1"
+    "PIC=1"
+  ];
+
+  # Build and install are based on http://wiki.dlang.org/Building_DMD
+  buildPhase = ''
+    runHook preBuild
+
+    export buildJobs=$NIX_BUILD_CORES
+    if [ -z $enableParallelBuilding ]; then
+      buildJobs=1
+    fi
+
+    make -C dmd -f posix.mak $buildFlags -j$buildJobs HOST_DMD=${HOST_DMD}
+    echo ${tzdata}/share/zoneinfo/ > TZDatabaseDirFile
+    echo ${lib.getLib curl}/lib/libcurl${stdenv.hostPlatform.extensions.sharedLibrary} > LibcurlPathFile
+    make -C phobos -f posix.mak $buildFlags -j$buildJobs DMD=${pathToDmd} DFLAGS="-version=TZDatabaseDir -version=LibcurlPath -J$PWD"
+
+    runHook postBuild
+  '';
+
+  doCheck = true;
+
+  checkFlags = buildFlags;
+
+  # many tests are disbled because they are failing
+
+  # NOTE: Purity check is disabled for checkPhase because it doesn't fare well
+  # with the DMD linker. See https://github.com/NixOS/nixpkgs/issues/97420
+  checkPhase = ''
+    runHook preCheck
+
+    export checkJobs=$NIX_BUILD_CORES
+    if [ -z $enableParallelChecking ]; then
+      checkJobs=1
+    fi
+
+    NIX_ENFORCE_PURITY= \
+      make -C dmd/compiler/test $checkFlags CC=$CXX SHELL=$SHELL -j$checkJobs N=$checkJobs
+
+    NIX_ENFORCE_PURITY= \
+      make -C phobos -f posix.mak unittest $checkFlags -j$checkJobs DFLAGS="-version=TZDatabaseDir -version=LibcurlPath -J$PWD"
+
+    runHook postCheck
+  '';
+
+  installPhase = ''
+    runHook preInstall
+
+    install -Dm755 ${pathToDmd} $out/bin/dmd
+
+    installManPage dmd/docs/man/man*/*
+
+    mkdir $out/lib
+    cp phobos/generated/${osname}/release/${bits}/libphobos2.* $out/lib/
+
+    wrapProgram $out/bin/dmd \
+      --prefix PATH ":" "${targetPackages.stdenv.cc}/bin" \
+      --set-default CC "${targetPackages.stdenv.cc}/bin/cc"
+
+    substitute ${dmdConfFile} "$out/bin/dmd.conf" --subst-var out
+
+    runHook postInstall
+  '';
+
+  meta = with lib; {
+    description = "Official reference compiler for the D language";
+    homepage = "https://dlang.org/";
+    # Everything is now Boost licensed, even the backend.
+    # https://github.com/dlang/dmd/pull/6680
+    license = licenses.boost;
+    maintainers = with maintainers; [ ThomasMader lionello dukc ];
+    platforms = [ "x86_64-linux" "i686-linux" "x86_64-darwin" ];
+  };
+}
diff --git a/nix-overlays/dtools/default.nix b/nix-overlays/dtools/default.nix
new file mode 100644
index 0000000..d605e4d
--- /dev/null
+++ b/nix-overlays/dtools/default.nix
@@ -0,0 +1,51 @@
+{ stdenv, lib, fetchFromGitHub, fetchpatch, ldc, curl, gnumake42 }:
+
+stdenv.mkDerivation rec {
+  pname = "dtools";
+  version = "2.103.1";
+
+  src = fetchFromGitHub {
+    owner = "dlang";
+    repo = "tools";
+    rev = "v${version}";
+    sha256 = "sha256-XM4gUxcarQCOBR8W/o0iWAI54PyLDkH6CsDce22Cnu4=";
+    name = "dtools";
+  };
+
+  patches = [
+    (fetchpatch {
+      # part of https://github.com/dlang/tools/pull/441
+      url = "https://github.com/dlang/tools/commit/6c6a042d1b08e3ec1790bd07a7f69424625ee866.patch"; # Fix LDC arm64 build
+      sha256 = "sha256-x6EclTYN1Y5FG57KLhbBK0BZicSYcZoWO7MTVcP4T18=";
+    })
+  ];
+
+  nativeBuildInputs = [ ldc gnumake42 ]; # fails with make 4.4
+  buildInputs = [ curl ];
+
+  makeCmd = ''
+    make -f posix.mak all DMD_DIR=dmd DMD=${ldc.out}/bin/ldmd2 CC=${stdenv.cc}/bin/cc
+  '';
+
+  buildPhase = ''
+    $makeCmd
+  '';
+
+  doCheck = true;
+
+  checkPhase = ''
+      $makeCmd test_rdmd
+    '';
+
+  installPhase = ''
+      $makeCmd INSTALL_DIR=$out install
+  '';
+
+  meta = with lib; {
+    description = "Ancillary tools for the D programming language compiler";
+    homepage = "https://github.com/dlang/tools";
+    license = lib.licenses.boost;
+    maintainers = with maintainers; [ ThomasMader ];
+    platforms = lib.platforms.unix;
+  };
+}
diff --git a/nix-overlays/dub/default.nix b/nix-overlays/dub/default.nix
new file mode 100644
index 0000000..0ebc576
--- /dev/null
+++ b/nix-overlays/dub/default.nix
@@ -0,0 +1,83 @@
+{ lib, stdenv, fetchFromGitHub, curl, libevent, rsync, ldc, dcompiler ? ldc }:
+
+assert dcompiler != null;
+
+stdenv.mkDerivation rec {
+  pname = "dub";
+  version = "1.30.0";
+
+  enableParallelBuilding = true;
+
+  src = fetchFromGitHub {
+    owner = "dlang";
+    repo = "dub";
+    rev = "v${version}";
+    sha256 = "sha256-iVl7bjblvIxvrUX7Phq6h4AIAmZjNVkGYYFA1hhsE7c=";
+  };
+
+  #postUnpack = ''
+  #  patchShebangs .
+  #'';
+
+  dubvar = "\\$DUB";
+  postPatch = ''
+    patchShebangs test
+
+    # Can be removed with https://github.com/dlang/dub/pull/1368
+    substituteInPlace test/fetchzip.sh \
+        --replace "dub remove" "\"${dubvar}\" remove"
+  '';
+
+  nativeBuildInputs = [ dcompiler libevent rsync ];
+  buildInputs = [ curl ];
+
+  buildPhase = ''
+    for DC_ in dmd ldmd2 gdmd; do
+      echo "... check for D compiler $DC_ ..."
+      export DC=$(type -P $DC_ || echo "")
+      if [ ! "$DC" == "" ]; then
+        break
+      fi
+    done
+    if [ "$DC" == "" ]; then
+      exit "Error: could not find D compiler"
+    fi
+    echo "$DC_ found and used as D compiler in buildPhase for $pname"
+    $DC ./build.d
+    ./build
+  '';
+
+  doCheck = !stdenv.isDarwin;
+
+  checkPhase = ''
+    export DUB=$NIX_BUILD_TOP/source/bin/dub
+    export PATH=$PATH:$NIX_BUILD_TOP/source/bin/
+    #export DC=${dcompiler.out}/bin/${if dcompiler.pname=="ldc" then "ldc2" else dcompiler.pname}
+    if [ "$DC" == "" ]; then
+      exit "Error: could not find D compiler"
+    fi
+    echo "DC out --> $DC"
+    export HOME=$TMP
+
+    rm -rf test/issue502-root-import
+    rm -rf test/dpath-variable
+    rm test/dpath-variable.sh
+    rm -rf test/git-dependency
+    rm -rf test/use-c-sources # added to build v1.33.0
+
+    ./test/run-unittest.sh
+  '';
+
+  installPhase = ''
+    mkdir -p $out/bin
+    cp bin/dub $out/bin
+  '';
+
+  meta = with lib; {
+    description = "Package and build manager for D applications and libraries";
+    homepage = "https://code.dlang.org/";
+    license = licenses.mit;
+    maintainers = with maintainers; [ ThomasMader ];
+    platforms = [ "x86_64-linux" "i686-linux" "aarch64-linux" "x86_64-darwin" "aarch64-darwin" ];
+  };
+}
diff --git a/nix-overlays/ldc/binary.nix b/nix-overlays/ldc/binary.nix
new file mode 100644
index 0000000..dd4d51c
--- /dev/null
+++ b/nix-overlays/ldc/binary.nix
@@ -0,0 +1,43 @@
+{ lib, stdenv, fetchurl, curl, tzdata, autoPatchelfHook, fixDarwinDylibNames, libxml2
+, version, hashes }:
+
+let
+  inherit (stdenv) hostPlatform;
+  OS = if hostPlatform.isDarwin then "osx" else hostPlatform.parsed.kernel.name;
+  ARCH = if hostPlatform.isDarwin && hostPlatform.isAarch64 then "arm64" else hostPlatform.parsed.cpu.name;
+in stdenv.mkDerivation {
+  pname = "ldc-bootstrap";
+  inherit version;
+
+  src = fetchurl rec {
+    name = "ldc2-${version}-${OS}-${ARCH}.tar.xz";
+    url = "https://github.com/ldc-developers/ldc/releases/download/v${version}/${name}";
+    sha256 = hashes."${OS}-${ARCH}" or (throw "missing bootstrap sha256 for ${OS}-${ARCH}");
+  };
+
+  dontConfigure = true;
+  dontBuild = true;
+
+  nativeBuildInputs = lib.optionals hostPlatform.isLinux [
+    autoPatchelfHook
+  ] ++ lib.optional hostPlatform.isDarwin fixDarwinDylibNames;
+
+  buildInputs = lib.optionals stdenv.hostPlatform.isLinux [ libxml2 stdenv.cc.cc ];
+
+  propagatedBuildInputs = [ curl tzdata ];
+
+  installPhase = ''
+    mkdir -p $out
+
+    mv bin etc import lib LICENSE README $out/
+  '';
+
+  meta = with lib; {
+    description = "The LLVM-based D Compiler";
+    homepage = "https://github.com/ldc-developers/ldc";
+    # from https://github.com/ldc-developers/ldc/blob/master/LICENSE
+    license = with licenses; [ bsd3 boost mit ncsa gpl2Plus ];
+    maintainers = with maintainers; [ ThomasMader lionello ];
+    platforms = [ "x86_64-linux" "x86_64-darwin" "aarch64-linux" "aarch64-darwin" ];
+  };
+}
diff --git a/nix-overlays/ldc/bootstrap.nix b/nix-overlays/ldc/bootstrap.nix
new file mode 100644
index 0000000..7724cbc
--- /dev/null
+++ b/nix-overlays/ldc/bootstrap.nix
@@ -0,0 +1,11 @@
+{ callPackage }:
+callPackage ./binary.nix {
+  version = "1.25.0";
+  hashes = {
+    # Get these from `nix-prefetch-url https://github.com/ldc-developers/ldc/releases/download/v1.19.0/ldc2-1.19.0-osx-x86_64.tar.xz` etc..
+    osx-x86_64 = "sha256-6iKnbS+oalLKmyS8qYD/wS21b7+O+VgsWG2iT4PrWPU=";
+    linux-x86_64 = "sha256-sfg47RdlsIpryc3iZvE17OtLweh3Zw6DeuNJYgpuH+o=";
+    linux-aarch64  = "sha256-UDZ43x4flSo+SfsPeE8juZO2Wtk2ZzwySk0ADHnvJBI=";
+    osx-arm64  = "sha256-O/x0vy0wwQFaDc4uWSeMhx+chJKqbQb6e5QNYf+7DCw=";
+  };
+}
diff --git a/nix-overlays/ldc/default.nix b/nix-overlays/ldc/default.nix
new file mode 100644
index 0000000..6fe637d
--- /dev/null
+++ b/nix-overlays/ldc/default.nix
@@ -0,0 +1,4 @@
+import ./generic.nix {
+  version = "1.33.0-beta1";
+  sha256 = "sha256-axyjDAWwxHmG2yPhL6P8cF6XvVvapfw0AWLjUrVRoug=";
+}
diff --git a/nix-overlays/ldc/generic.nix b/nix-overlays/ldc/generic.nix
new file mode 100644
index 0000000..f88f448
--- /dev/null
+++ b/nix-overlays/ldc/generic.nix
@@ -0,0 +1,137 @@
+{ version, sha256 }:
+{ lib, stdenv, fetchurl, cmake, ninja, llvm_14, curl, tzdata
+, libconfig, lit, gdb, unzip, darwin, bash
+, callPackage, makeWrapper, runCommand, targetPackages
+, ldcBootstrap ? callPackage ./bootstrap.nix { }
+}:
+
+let
+  pathConfig = runCommand "ldc-lib-paths" {} ''
+    mkdir $out
+    echo ${tzdata}/share/zoneinfo/ > $out/TZDatabaseDirFile
+    echo ${curl.out}/lib/libcurl${stdenv.hostPlatform.extensions.sharedLibrary} > $out/LibcurlPathFile
+  '';
+
+in
+
+stdenv.mkDerivation rec {
+  pname = "ldc";
+  inherit version;
+
+  src = fetchurl {
+    url = "https://github.com/ldc-developers/ldc/releases/download/v${version}/ldc-${version}-src.tar.gz";
+    inherit sha256;
+  };
+
+  # https://issues.dlang.org/show_bug.cgi?id=19553
+  hardeningDisable = [ "fortify" ];
+
+  postUnpack = ''
+    patchShebangs .
+  ''
+  + ''
+      rm ldc-${version}-src/tests/dmd/fail_compilation/mixin_gc.d
+      rm ldc-${version}-src/tests/dmd/runnable/xtest46_gc.d
+      rm ldc-${version}-src/tests/dmd/runnable/testptrref_gc.d
+
+      # test depends on current year
+      rm ldc-${version}-src/tests/dmd/compilable/ddocYear.d
+  ''
+  + lib.optionalString stdenv.hostPlatform.isDarwin ''
+      # https://github.com/NixOS/nixpkgs/issues/34817
+      rm -r ldc-${version}-src/tests/plugins/addFuncEntryCall
+  '';
+
+  postPatch = ''
+    # Setting SHELL=$SHELL when dmd testsuite is run doesn't work on Linux somehow
+    substituteInPlace tests/dmd/Makefile --replace "SHELL=/bin/bash" "SHELL=${bash}/bin/bash"
+  ''
+  + lib.optionalString stdenv.hostPlatform.isLinux ''
+      substituteInPlace runtime/phobos/std/socket.d --replace "assert(ih.addrList[0] == 0x7F_00_00_01);" ""
+  ''
+  + lib.optionalString stdenv.hostPlatform.isDarwin ''
+      substituteInPlace runtime/phobos/std/socket.d --replace "foreach (name; names)" "names = []; foreach (name; names)"
+  '';
+
+  nativeBuildInputs = [
+    cmake ldcBootstrap lit lit.python llvm_14.dev makeWrapper ninja unzip
+  ]
+  ++ lib.optionals stdenv.hostPlatform.isDarwin [
+    darwin.apple_sdk.frameworks.Foundation
+  ]
+  ++ lib.optionals (!stdenv.hostPlatform.isDarwin) [
+    # https://github.com/NixOS/nixpkgs/pull/36378#issuecomment-385034818
+    gdb
+  ];
+
+  buildInputs = [ curl tzdata ];
+
+  cmakeFlags = [
+    "-DD_FLAGS=-d-version=TZDatabaseDir;-d-version=LibcurlPath;-J${pathConfig}"
+    "-DCMAKE_BUILD_TYPE=Release"
+  ];
+
+  postConfigure = ''
+    export DMD=$PWD/bin/ldmd2
+  '';
+
+  makeFlags = [ "DMD=$DMD" ];
+
+  fixNames = lib.optionalString stdenv.hostPlatform.isDarwin  ''
+    fixDarwinDylibNames() {
+      local flags=()
+
+      for fn in "$@"; do
+        flags+=(-change "$(basename "$fn")" "$fn")
+      done
+
+      for fn in "$@"; do
+        if [ -L "$fn" ]; then continue; fi
+        echo "$fn: fixing dylib"
+        install_name_tool -id "$fn" "''${flags[@]}" "$fn"
+      done
+    }
+
+    fixDarwinDylibNames $(find "$(pwd)/lib" -name "*.dylib")
+    export DYLD_LIBRARY_PATH=$(pwd)/lib
+  '';
+
+  # https://github.com/ldc-developers/ldc/issues/2497#issuecomment-459633746
+  additionalExceptions = lib.optionalString stdenv.hostPlatform.isDarwin
+    "|druntime-test-shared";
+
+  checkPhase = ''
+    # Build default lib test runners
+    ninja -j$NIX_BUILD_CORES all-test-runners
+
+    ${fixNames}
+
+    # Run dmd testsuite
+    export DMD_TESTSUITE_MAKE_ARGS="-j$NIX_BUILD_CORES DMD=$DMD"
+    ctest -V -R "dmd-testsuite"
+
+    # Build and run LDC D unittests.
+    ctest --output-on-failure -R "ldc2-unittest"
+
+    # Run LIT testsuite.
+    ctest -V -R "lit-tests"
+
+    # Run default lib unittests
+    ctest -j$NIX_BUILD_CORES --output-on-failure -E "ldc2-unittest|lit-tests|dmd-testsuite${additionalExceptions}"
+  '';
+
+  postInstall = ''
+    wrapProgram $out/bin/ldc2 \
+        --prefix PATH ":" "${targetPackages.stdenv.cc}/bin" \
+        --set-default CC "${targetPackages.stdenv.cc}/bin/cc"
+   '';
+
+  meta = with lib; {
+    description = "The LLVM-based D compiler";
+    homepage = "https://github.com/ldc-developers/ldc";
+    # from https://github.com/ldc-developers/ldc/blob/master/LICENSE
+    license = with licenses; [ bsd3 boost mit ncsa gpl2Plus ];
+    maintainers = with maintainers; [ ThomasMader lionello ];
+    platforms = [ "x86_64-linux" "i686-linux" "aarch64-linux" "x86_64-darwin" "aarch64-darwin" ];
+  };
+}
diff --git a/org/config_env.org b/org/config_env.org
index 171316f..2f8a111 100644
--- a/org/config_env.org
+++ b/org/config_env.org
@@ -83,6 +83,27 @@ direnv fetchurl https://raw.githubusercontent.com/nix-community/nix-direnv/${Nix
 
 - bespoke modify appropriately and generate if needed
 
+#+HEADER: :tangle ../.envrc-local
+#+HEADER: :noweb yes
+#+BEGIN_SRC sh
+if [[ ! -d ./.git ]]; then
+  git init
+  git add .
+fi
+echo '
+  .envrc-local echo ❯❯
+
+  ❯❯ nix flake update && nix flake check --show-trace && nix flake show && nix develop ".#devShell" -c zsh
+
+  ❯❯ nix develop
+  ❯❯ nix develop -c zsh
+  ❯❯ nix develop ".#dsh-overlay-ldc" --print-build-logs
+
+  ❯❯ nix build
+  ❯❯ nix build ".#default" --print-build-logs
+'
+#+END_SRC
+
 #+HEADER: :tangle ../.envrc-local_
 #+HEADER: :noweb yes
 #+BEGIN_SRC sh
diff --git a/org/config_git.org b/org/config_git.org
index 99f4e57..89db936 100644
--- a/org/config_git.org
+++ b/org/config_git.org
@@ -34,9 +34,12 @@
 !*.nix
 !flake.lock
 !.envrc
+!.envrc-local
 !.envrc-nix
 !.env
 !.env/**
+!nix-overlays
+!nix-overlays/**
 !README.md
 !README
 !COPYRIGHT
diff --git a/org/config_make.org b/org/config_make.org
index ba19a4c..ccf2614 100644
--- a/org/config_make.org
+++ b/org/config_make.org
@@ -48,7 +48,7 @@
 #+HEADER: :tangle ../makefile
 #+HEADER: :noweb yes
 #+BEGIN_SRC makefile
-include .envrc-local
+#include .envrc-local
 PROG_VER_GIT :=$(shell echo `git describe --long --tags | sed -e "s/^[ a-z_-]\+\([0-9.]\+\)/\1/;s/\([^-]*-g\)/r\1/;s/-/./g"`)
 PROG_VER_DECLARED :=$(shell echo `cat ./views/version.txt | grep --color=never "enum" | sed 's/.\+(\([0-9]\+\),[ \t]\+\([0-9]\+\),[ \t]\+\([0-9]\+\)[ \t]*).\+/\1.\2.\3/g'`)
 DUB=dub
@@ -481,44 +481,6 @@ spineWWWrsyncLinode:
 	rsync -v /var/www/sqlite/spine.search.db linode:./stage/. ; \
 	echo "tar -xf ../spine_output.$${Date}.tar.bz2"
 
-# get project external dependencies
-depends_get:
-	dub upgrade; \
-	cd $${gwd} && \
-	echo "$${dirs_loc}" && \
-	for dir in $${dirs_loc}; do \
-	  if [[ -d $${dir} ]]; then \
-	    echo $${gwd}/$${dir} && \
-	    if [[ "imageformats" == $${dir} ]]; then \
-	      echo $${gwd}/$${dir} && \
-	      rm -rvf $${gwd}/$${dir} && \
-	      git clone --depth=1 https://github.com/tjhann/$${dir} && \
-	      cd $${dir} && \
-	      echo $$PWD && \
-	      echo "$${dir} `git rev-parse HEAD | cut -c 1-8`"   > ../$${dir}.meta && \
-	      echo "https://github.com/tjhann/$${dir}"           >> ../$${dir}.meta && \
-	      echo "Boost Software License 1.0 (BSL-1.0)"       >> ../$${dir}.meta && \
-	      cd $${gwd} && \
-	      rm -rf $${gwd}/$${dir}/.git; \
-	    elif [[ "d2sqlite3" == $${dir}  || "D-YAML" == $${dir} || "tinyendian" == $${dir} ]]; then \
-	      echo $${gwd}/$${dir} && \
-	      rm -rvf $${gwd}/$${dir} && \
-	      git clone --depth=1 https://github.com/dlang-community/$${dir} && \
-	      cd $${gwd}/$${dir} && \
-	      echo "$${dir} `git rev-parse HEAD | cut -c 1-8`"   > ../$${dir}.meta && \
-	      echo "https://github.com/dlang-community/$${dir}"  >> ../$${dir}.meta && \
-	      echo "Boost Software License 1.0 (BSL-1.0)"       >> ../$${dir}.meta && \
-	      cd $${gwd} && \
-	      rm -rf $${gwd}/$${dir}/.git; \
-	    fi; \
-	  fi; \
-	done; \
-	cd $${hwd}
-
-# get and set project external dependencies
-depends_set: depends_get
-	dub describe | sed 's~$(shell echo `pwd | sed 's_/_\\/_g'`)~.~g'  > dub_describe.json
-
 changelog_:
 	git log --pretty=format:'---%+s %+as %ae%+h%d%+b' --no-merges | sed "/^\\s*$$/d" | sed "s/^---$$//" | sed "s/^\(\*\)\+/-/" | sed "s/ \+$$//" > CHANGELOG_
 
@@ -566,16 +528,19 @@ nixGitHEADtarballBuild:
 # clean create check & build test tarball
 nixGitHEADtarball: nixGitHEADtarballClean nixGitHEADtarballTar nixGitHEADtarballCheck nixGitHEADtarballBuild
 
+# get project external dependencies
 get_depends:
 	hwd=$$(echo `pwd`) && \
 	gwd="$${hwd}/src/ext_depends" && \
-	dirs=$$(echo `ls -gx $${gwd}`) && \
 	license_bsl="Boost Software License 1.0 (BSL-1.0)" && \
 	echo $${hwd} && \
 	echo $${gwd} && \
-	echo $${deps} && \
 	dub upgrade; \
+	if [ ! -d $${gwd} ]; then \
+	  mkdir -p $${gwd}/{d2sqlite3,D-YAML,imageformats,tinyendian}; \
+	fi; \
 	cd $${gwd} && \
+	deps=`ls -gx '.'` && \
 	for dir in $${deps}; do \
 	  if [ -d $${dir} ]; then \
 	    echo $${dir} && \
@@ -605,6 +570,7 @@ get_depends:
 	done; \
 	cd $${hwd}
 
+# get and set project external dependencies
 set_depends: get_depends
 	dub describe | sed 's~$(shell echo `pwd | sed 's_/_\\/_g'`)~.~g'  > dub_describe.json
 
diff --git a/org/config_nix.org b/org/config_nix.org
index e5e0739..ee9b157 100644
--- a/org/config_nix.org
+++ b/org/config_nix.org
@@ -42,6 +42,18 @@
       dub test --combined --skip-registry=all
       runHook postCheck
     '';
+    localOverlay = (final: prev: {
+      ldc = prev.callPackage ./nix-overlays/ldc {  };
+      dmd = prev.callPackage ./nix-overlays/dmd {  };
+      dub = prev.callPackage ./nix-overlays/dub {  };       # -> ?
+      #gdc = prev.callPackage ./nix-overlays/gdc {  };      # empty
+    });
+    pkgsForSystem = system: import nixpkgs {
+      overlays = [
+        localOverlay
+      ];
+      inherit system;
+    };
     installPhase = ''
       runHook preInstall
       mkdir -p $out/bin
@@ -54,9 +66,10 @@
     '';
   in {
     packages = forAllSystems (system: let
+      pkgs-ovl = pkgsForSystem system;
       pkgs = nixpkgsFor.${system};
     in
-      with pkgs; {
+      with pkgs-ovl; {
         default = stdenv.mkDerivation {
           inherit pname;
           inherit version;
@@ -76,7 +89,7 @@
             done
             if [ "$DC" == "" ]; then exit "Error: could not find D compiler"; fi
             echo "$DC_ used as D compiler to build $pname"
-            dub build --compiler=$DC --build=$DC_ --combined --skip-registry=all
+            dub build --cache=local --compiler=$DC --build=$DC_ --combined --skip-registry=all
             runHook postBuild
           '';
           inherit checkPhase;
@@ -95,7 +108,7 @@
           nativeBuildInputs = [dub dmd gnumake];
           buildPhase = ''
             runHook preBuild
-            dub build --compiler=$(type -P dmd) --build=dmd --combined --skip-registry=all
+            dub build --cache=local --compiler=$(type -P dmd) --build=dmd --combined --skip-registry=all
             runHook postBuild
           '';
           inherit checkPhase;
@@ -114,7 +127,7 @@
           nativeBuildInputs = [dub ldc gnumake];
           buildPhase = ''
             runHook preBuild
-            dub build --compiler=$(type -P ldc2) --build=ldc2 --combined --skip-registry=all
+            dub build --cache=local --compiler=$(type -P ldc2) --build=ldc2 --combined --skip-registry=all
             runHook postBuild
           '';
           inherit checkPhase;
@@ -133,7 +146,7 @@
         #  nativeBuildInputs = [ dub gdc gnumake ];
         #  buildPhase = ''
         #    runHook preBuild
-        #    dub build --compiler=$(type -P gdc) --build=gdc --combined --skip-registry=all
+        #    dub build --cache=local --compiler=$(type -P gdc) --build=gdc --combined --skip-registry=all
         #    runHook postBuild
         #  '';
         #  inherit checkPhase;
@@ -149,13 +162,14 @@
       };
     });
     devShells = forAllSystems (system: let
+      pkgs-ovl = pkgsForSystem system;
       pkgs = nixpkgsFor.${system};
       shellHook = ''
-        export DFLAGS="-O2 -inline -boundscheck=on -color=on"
+        export DFLAGS="-O2 -boundscheck=on"
         export Date=`date "+%Y%m%d"`
       '';
     in
-      with pkgs; {
+      with pkgs-ovl; {
         devShell = mkShell {
           name = "spine base dev shell";
           inherit shell;
@@ -164,9 +178,37 @@
           #nativeBuildInputs = [ dub dmd ldc gdc gnumake ];
           packages = [
             sqlite
-            dub
+            ldc
             #dmd
+            dub
+            gnumake
+          ];
+          inherit shellHook;
+        };
+        devShell-dmd = mkShell {
+          name = "spine base dev shell";
+          inherit shell;
+          inherit devEnv;
+          #buildInputs = [ sqlite ];
+          #nativeBuildInputs = [ dub dmd ldc gdc gnumake ];
+          packages = [
+            sqlite
+            dmd
+            dub
+            gnumake
+          ];
+          inherit shellHook;
+        };
+        devShell-ldc = mkShell {
+          name = "spine base dev shell";
+          inherit shell;
+          inherit devEnv;
+          #buildInputs = [ sqlite ];
+          #nativeBuildInputs = [ dub dmd ldc gdc gnumake ];
+          packages = [
+            sqlite
             ldc
+            dub
             gnumake
           ];
           inherit shellHook;
@@ -177,7 +219,7 @@
           inherit devEnv;
           packages = [
             dub
-            dmd
+            #dmd
             ldc
             gnumake
             sqlite
@@ -910,3 +952,15 @@ postInstall:
 	echo "$${out}/share/cgi-bin"; \
 	echo `ls -la $${out}/bin/spine`
 #+END_SRC
+
+** empty sha56 hash
+
+#+NAME: blank_hash
+#+BEGIN_SRC nix
+sha256-0000000000000000000000000000000000000000000=
+#+END_SRC
+
+#+NAME: assumed_hash
+#+BEGIN_SRC nix
+sha256-AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=
+#+END_SRC
diff --git a/org/nixpkgs_overlays_d_related.org b/org/nixpkgs_overlays_d_related.org
new file mode 100644
index 0000000..fac294d
--- /dev/null
+++ b/org/nixpkgs_overlays_d_related.org
@@ -0,0 +1,1668 @@
+-*- mode: org -*-
+#+TITLE:       D nix, dev shells with overlays
+#+DESCRIPTION: dlang related nixpkgs of interest (dlang cvompilers & tools)
+#+FILETAGS:    :nixos:nixpkgs:dlang:compiler:
+#+AUTHOR:      Ralph Amissah
+#+EMAIL:       [[mailto:ralph.amissah@gmail.com][ralph.amissah@gmail.com]]
+#+COPYRIGHT:   Copyright (C) 2020 Ralph Amissah
+#+LICENSE:     Boost Software License 1.0
+#+LANGUAGE:    en
+#+STARTUP:     show3levels hideblocks hidestars noindent entitiespretty
+#+PROPERTY:    header-args  :exports code
+#+PROPERTY:    header-args+ :noweb yes
+#+PROPERTY:    header-args+ :results no
+#+PROPERTY:    header-args+ :cache no
+#+PROPERTY:    header-args+ :padline no
+#+PROPERTY:    header-args+ :mkdirp yes
+#+OPTIONS:     H:3 num:nil toc:t \n:nil @:t ::t |:t ^:nil _:nil -:t f:t *:t <:t
+
+* nix ( written to ./dlang-nix-flakes/ )
+** README
+
+#+HEADER: :tangle "../nix-overlays/README"
+#+BEGIN_SRC org
+-*- mode: org -*-
+,#+TITLE:       D related overlays
+,#+DESCRIPTION: ldc, dub, dtools: dlang compiler build tool and tools
+,#+FILETAGS:    :dlang:build:tools:
+,#+AUTHOR:      Ralph Amissah
+,#+EMAIL:       [[mailto:ralph.amissah@gmail.com][ralph.amissah@gmail.com]]
+,#+COPYRIGHT:   Copyright (C) 2015 - 2023 Ralph Amissah
+,#+LANGUAGE:    en
+,#+STARTUP:     content hideblocks hidestars noindent entitiespretty
+,#+OPTIONS:     H:3 num:nil toc:t \n:nil @:t ::t |:t ^:nil _:nil -:t f:t *:t <:t
+,#+PROPERTY:    header-args  :exports code
+,#+PROPERTY:    header-args+ :noweb yes
+,#+PROPERTY:    header-args+ :eval no
+,#+PROPERTY:    header-args+ :results no
+,#+PROPERTY:    header-args+ :cache no
+,#+PROPERTY:    header-args+ :padline no
+
+,* README for D related overlays
+,** dlang-nix-overlays
+
+Nix build overlays for building and testing more recent versions of the dlang
+compiler and build tools: ldc, dub and dtools, than exist in nixpkgs at the time
+of publishing, in some cases with additional fixes.
+
+nix overlays for (updates nixpkgs, more recent versions of):
+  - ldc     ( 1.30.0 -> <<ldc_version>> )
+  - dub     ( 1.23.0 -> <<dub_version>> ) [for nix versions 1.31.0 ... 1.33.0 broken]
+  - dtools  ( 2.095.1 -> <<dtools_version>> )
+
+  - dmd     ( 2.100.2 -> <<dmd_version>> ) KO ✗
+  - gdc     [not yet available]
+
+(updates nixpkgs circa 2023-05-12)
+
+dlang-nix-flakes.org --❯
+  .
+  └── nix-overlays
+      ├── dmd
+      │   ├── binary.nix
+      │   ├── bootstrap.nix
+      │   ├── default.nix
+      │   └── generic.nix
+      ├── dtools
+      │   └── default.nix
+      ├── dub
+      │   └── default.nix
+      ├── ldc
+      │   ├── binary.nix
+      │   ├── bootstrap.nix
+      │   ├── default.nix
+      │   └── generic.nix
+      └── README
+
+search nixpkgs here:
+
+- https://search.nixos.org/packages?channel=unstable&from=0&size=100&sort=relevance&query=
+
+,** compilers
+,*** ldc OK ✓ ( 1.30.0 -> <<ldc_version>> )
+
+- https://wiki.dlang.org/LDC
+
+- https://github.com/ldc-developers/ldc
+  - https://github.com/ldc-developers/ldc/releases
+    nix-prefetch-url --unpack https://github.com/ldc-developers/ldc/archive/refs/tags/v<<ldc_version>>.tar.gz
+  - https://github.com/ldc-developers/ldc/issues
+
+- version in nixpkgs:
+  - https://search.nixos.org/packages?channel=unstable&show=ldc&from=0&size=100&sort=relevance&type=packages&query=ldc
+
+,*** dmd KO ✗ ( 2.100.2 -> <<dmd_version>> )
+
+- https://dlang.org/
+  - https://wiki.dlang.org/LDC
+
+- https://github.com/dlang/dmd
+  - https://github.com/dlang/dmd/tags
+    nix-prefetch-url --unpack https://github.com/dlang/dmd/archive/refs/tags/v<<dmd_version>>.tar.gz
+  - https://github.com/dlang/dmd/pulls
+
+- version in nixpkgs:
+  - https://search.nixos.org/packages?channel=unstable&show=dmd&from=0&size=100&sort=relevance&type=packages&query=dmd
+
+- dmd nixpkg modified and appears to build ok, but it appears my overlay does
+  not get things right REVIEW
+
+- dmd on nixos FAILS to build (my working projects), appears not to find parts
+  of itself
+
+,*** gdc ( not provided yet with gcc12 in nixpkgs )
+
+not yet provided in nixpkgs with gcc12, no attempt made
+
+- https://wiki.dlang.org/GDC
+  - https://wiki.dlang.org/GDC_Development
+
+- https://github.com/D-Programming-GDC/gdc
+
+,** build tool
+,*** dub ( 1.23.0 -> <<dub_version>> )
+
+- https://code.dlang.org/packages/dub
+
+- https://github.com/dlang/dub
+  - https://github.com/dlang/dub/releases
+    nix-prefetch-url --unpack https://github.com/dlang/dub/archive/refs/tags/v<<dub_version>>.tar.gz
+  - https://github.com/dlang/dub/issues
+
+- version in nixpkgs:
+  - https://search.nixos.org/packages?channel=unstable&show=dub&from=0&size=100&sort=relevance&type=packages&query=dub
+
+- dub nixpkg overlay is updated and runs most dub tests correctly
+
+- dub from v1.31.0 FAILS to build packages with nix tools that previous version
+  of dub built (from v1.23.0 to v1.30.0 which is currently in nixpkgs); FAILURE
+  is from v1.31.0 through v1.32.1 (which is current at the time of this commit)
+
+,** tools
+,*** dtools OK ✓ ( 2.095.1 -> <<dtools_version>> )
+
+- https://code.dlang.org/packages/dtools
+
+- https://github.com/dlang/tools
+  - https://github.com/dlang/tools/tags
+    nix-prefetch --unpack https://github.com/dlang/tools/archive/refs/tags/v<<dtools_version>>.tar.gz
+  - https://github.com/dlang/tools/issues
+
+- version in nixpkgs
+  - https://search.nixos.org/packages?channel=unstable&show=dtools&from=0&size=100&sort=relevance&type=packages&query=dtools
+
+,** nixpkgs
+
+It is possible to work directly against a local copy of nixpkgs. To do so you
+would clone nixpkgs and point to the local nixpkgs as your build source.
+
+git clone --depth=1 --branch master https://github.com/nixos/nixpkgs nixpkgs
+
+- ./nixpkgs/pkgs/development/compilers/ldc
+- ./nixpkgs/pkgs/development/compilers/dmd
+- ./nixpkgs/pkgs/development/tools/build-managers/dub
+- ./nixpkgs/pkgs/development/tools/dtools
+
+- ./nixpkgs/pkgs/development/compilers/gcc
+
+Note the overlays if copied to the nixpkgs path locations should work as they do
+in the overlay, with a pointer to the cloned nixpkgs as nixpkgs repository
+source. In fact the starting point for the overlays was to take verbatim what
+was in nixpkgs and then to update and fix where necessary those packages.
+
+It is possible to compare the changes made by the overlays here directly against
+what is currently available in nixpkgs.
+
+- https://search.nixos.org/packages?channel=unstable&size=100&sort=relevance&query=
+
+#+END_SRC
+
+** .gitignore
+
+#+HEADER: :tangle-NO "../nix-overlays/.gitignore"
+#+BEGIN_SRC sh
+# git ls-files --others --exclude-from=.git/info/exclude
+# git check-ignore -v flake.lock
+# git clean -ix
+# find . -name "*_" | xargs rm -rf
+# find . -name "*.o" | xargs rm -rf
+,*
+!.gitignore
+!.envrc
+!.envrc-local
+!.envrc-nix
+!flake.nix
+!flake.lock
+!nix-overlays
+!nix-overlays/**
+!shell.nix
+!makefile
+!justfile
+!README
+!*.nix
+!*.org
+!*.sh
+!*.txt
+
+# EXCLUDED Files & directories - ensure excluded
+.dub/**
+tmp/**
+,*_.org
+,*_.nix
+,*_.d
+,*_.txt
+,*_
+,*.swp
+,*~
+,*.\#*
+\#*
+#+END_SRC
+
+** .env*
+*** .envrc
+
+#+HEADER: :tangle-NO "../nix-overlays/.envrc"
+#+BEGIN_SRC sh
+if [ -f .envrc-local ]; then
+  source_env_if_exists .envrc-local || source .envrc-local
+fi
+if [ -f .envrc-nix ]; then
+  source_env_if_exists .envrc-nix || source .envrc-nix
+fi
+#+END_SRC
+
+*** .envrc-local
+
+#+HEADER: :tangle-NO "../nix-overlays/.envrc-local"
+#+BEGIN_SRC sh
+#if [[ !( -f ./nix-flakes.org) && -f ../dlang-nix-flakes.org ]]; then
+#  # for editing purpose link to the .org file that creates ./dlang-nix-flakes/ content
+#  ln -s ../dlang-nix-flakes.org ./nix-flakes.org
+#fi
+if [[ ! -d ./.git ]]; then
+  git init
+  git add .
+fi
+#eval "$(nix print-dev-env)"
+echo '
+  .envrc-local echo ❯❯
+
+  ❯❯ nix flake update && nix flake check --show-trace && nix flake show && nix develop ".#devShell" -c zsh
+
+  ❯❯ nix develop
+  ❯❯ nix develop -c zsh
+  ❯❯ nix develop ".#dsh-overlay-ldc" --print-build-logs
+
+  ❯❯ nix build
+  ❯❯ nix build ".#default" --print-build-logs
+'
+#+END_SRC
+
+*** .envrc-nix
+
+- https://github.com/nix-community/nix-direnv
+- NixDirEnvSHA="sha256-0000000000000000000000000000000000000000000="
+- direnv fetchurl https://raw.githubusercontent.com/nix-community/nix-direnv/${NixDirEnvVersion}/direnvrc
+
+#+HEADER: :tangle-NO "../nix-overlays/.envrc-nix"
+#+BEGIN_SRC sh
+NIX_ENFORCE_PURITY=1
+# - https://github.com/nix-community/nix-direnv
+NixDirEnvVersion="2.3.0"
+NixDirEnvSHA="sha256-Dmd+j63L84wuzgyjITIfSxSD57Tx7v51DMxVZOsiUD8="
+if ! has nix_direnv_version || ! nix_direnv_version ${NixDirEnvVersion}; then
+  source_url "https://raw.githubusercontent.com/nix-community/nix-direnv/${NixDirEnvVersion}/direnvrc" "${NixDirEnvSHA}"
+fi
+watch_file flake.lock
+watch_file flake.nix
+watch_file shell.nix
+watch_file makefile
+watch_file .envrc
+watch_file .envrc-local
+watch_file .envrc-nix
+nix_direnv_watch_file flake.nix
+nix_direnv_watch_file shell.nix
+nix_direnv_watch_file .envrc
+nix_direnv_watch_file .envrc-local
+nix_direnv_watch_file .envrc-nix
+nix flake update
+nix flake check
+nix flake show
+echo ""
+PATH_add result/bin
+use flake .
+#use flake .#default
+#+END_SRC
+
+** .nix
+*** flake.nix
+
+#+HEADER: :tangle-NO "../nix-overlays/flake.nix"
+#+BEGIN_SRC nix
+{
+  description = "dub d package manager";
+  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+  inputs.flake-utils.url = "github:numtide/flake-utils";
+  outputs = {
+    self,
+    nixpkgs,
+    flake-utils,
+  } @ inputs: let
+    name = "dev-dub";
+    shell = ./shell.nix;
+    devEnv = ./.envrc;
+    supportedSystems = ["x86_64-linux"];
+    forAllSystems = nixpkgs.lib.genAttrs supportedSystems;
+    nixpkgsFor = forAllSystems (system: import nixpkgs {inherit system;});
+    checkPhase = ''
+      runHook preCheck
+      #dub test --combined --skip-registry=all
+      runHook postCheck
+    '';
+    localOverlay = (final: prev: {
+      ldc = prev.callPackage ./nix-overlays/ldc {  };       # -> ok <<ldc_version>>
+      dmd = prev.callPackage ./nix-overlays/dmd {  };       # -> ok <<dmd_version>>
+      dub = prev.callPackage ./nix-overlays/dub {  };       # -> ? <<dub_version>>
+      dtools = prev.callPackage ./nix-overlays/dtools {  }; # -> ok <<dtools_version>>
+      #gdc = prev.callPackage ./nix-overlays/gdc {  };      # empty
+    });
+    pkgsForSystem = system: import nixpkgs {
+      overlays = [
+        localOverlay
+      ];
+      inherit system;
+    };
+  in {
+    packages = forAllSystems (system: let
+      pkgs-ovl = pkgsForSystem system;
+      pkgs = nixpkgsFor.${system};
+    in
+      with pkgs-ovl; {
+        default = dub;
+      });
+    devShells = forAllSystems (system: let
+      pkgs-ovl = pkgsForSystem system;
+      pkgs = nixpkgsFor.${system};
+      shellHook = ''
+      '';
+    in
+      with pkgs-ovl; {
+        dsh-overlay-dtools = mkShell {
+          name = "overlay - ldc-<<ldc_version>> - dub-<<dub_version>> - dtools-<<dtools_version>>";
+          inherit shell;
+          inherit devEnv;
+          packages = [
+            gnumake
+            ldc
+            dub
+            dtools
+          ];
+          inherit shellHook;
+        };
+        dsh-overlay-ldc-dub = mkShell {
+          name = "overlay - ldc-<<ldc_version>> - dub-<<dub_version>>";
+          inherit shell;
+          inherit devEnv;
+          packages = [
+            gnumake
+            ldc
+            dub
+          ];
+          inherit shellHook;
+        };
+        dsh-overlay-dmd-dub = mkShell {
+          name = "overlay - dmd-<<dmd_version>> - dub-<<dub_version>> - broken";
+          inherit shell;
+          inherit devEnv;
+          packages = [
+            gnumake
+            dmd
+            dub
+          ];
+          inherit shellHook;
+        };
+        dsh-overlay-dtest-tilix = mkShell {
+          name = "overlay - ldc-<<ldc_version>> - dub-<<dub_version>> - tilix - gtkd";
+          inherit shell;
+          inherit devEnv;
+          packages = [
+            gnumake
+            ldc
+            gtkd
+            tilix
+            dub
+          ];
+          inherit shellHook;
+        };
+        #dsh-overlay-gdc = mkShell {
+        #  name = "dub + gdc dev shell";
+        #  inherit shell;
+        #  inherit devEnv;
+        #  packages = [
+        #    gnumake
+        #    gdc
+        #    dub
+        #  ];
+        #  inherit shellHook;
+        #};
+        dsh-nixpkgs-ldc-dub = mkShell {
+          name = "nixpkgs - ldc - dub";
+          inherit shell;
+          inherit devEnv;
+          #nativeBuildInputs = [ dub dmd ldc gdc gnumake ];
+          #buildInputs = [ sqlite ];
+          packages = with pkgs; [
+            ldc
+            dub
+            gnumake
+          ];
+          inherit shellHook;
+        };
+        default = import ./shell.nix {inherit pkgs;};
+      });
+  };
+}
+#+END_SRC
+
+*** shell.nix
+
+#+HEADER: :tangle-NO "../nix-overlays/shell.nix"
+#+HEADER: :tangle-mode (identity #o755)
+#+HEADER: :shebang "#!/usr/bin/env -S nix-shell -I nixpkgs=/srv/nix/nixpkgs --pure\n#!nix-shell -i bash"
+#+BEGIN_SRC nix
+{pkgs ? import <nixpkgs> {}}:
+with pkgs;
+  mkShell {
+    buildInputs = [
+      # ❯❯❯ nix_related
+      nix
+      direnv
+      nixVersions.unstable
+      nix-prefetch-git
+      validatePkgConfig
+      nix-output-monitor
+      #nix-tree
+      #nvd
+      jq
+      alejandra
+      git
+      # ❯❯❯ dev
+      ldc
+      #rund
+      dub
+      #dtools
+      # ❯❯❯ test
+      #tilix
+      #gtkd
+    ];
+    shellHook = ''
+      #echo '
+      #  shell.nix echo ❯❯
+
+      #  ❯❯ nix flake update && nix flake check --show-trace && nix flake show && nix develop ".#devShell" -c zsh
+      #'
+    '';
+  }
+#+END_SRC
+
+*** default.nix
+
+will automatically build the default development shell, perhaps unecessary
+
+#+HEADER: :tangle-NO "../nix-overlays/default.nix"
+#+HEADER: :tangle-mode (identity #o755)
+#+HEADER: :shebang #!/usr/bin/env -S nix-build
+#+BEGIN_SRC nix
+{pkgs ? import <nixpkgs> {}}:
+pkgs.callPackage ./shell.nix {}
+#+END_SRC
+
+* nixpkgs overlays ( written to ./dlang-nix-flakes/nix-overlays/ )
+** ldc OK ✓
+*** info
+**** links
+
+- https://wiki.dlang.org/LDC
+
+- https://github.com/ldc-developers/ldc
+  - https://github.com/ldc-developers/ldc/releases
+  - https://github.com/ldc-developers/ldc/issues
+
+- version in nixpkgs:
+  - https://search.nixos.org/packages?channel=unstable&show=ldc&from=0&size=100&sort=relevance&type=packages&query=ldc
+
+**** notes
+
+- OK ldc 1.32.2 tested
+
+*** overlays
+**** default.nix OK ✓
+
+#+HEADER: :tangle "../nix-overlays/ldc/default.nix"
+#+BEGIN_SRC nix
+import ./generic.nix {
+  <<ldc_version_info>>
+}
+#+END_SRC
+
+**** generic.nix OK ✓ (unaltered)
+
+#+HEADER: :tangle "../nix-overlays/ldc/generic.nix"
+#+BEGIN_SRC nix
+{ version, sha256 }:
+{ lib, stdenv, fetchurl, cmake, ninja, llvm_14, curl, tzdata
+, libconfig, lit, gdb, unzip, darwin, bash
+, callPackage, makeWrapper, runCommand, targetPackages
+, ldcBootstrap ? callPackage ./bootstrap.nix { }
+}:
+
+let
+  pathConfig = runCommand "ldc-lib-paths" {} ''
+    mkdir $out
+    echo ${tzdata}/share/zoneinfo/ > $out/TZDatabaseDirFile
+    echo ${curl.out}/lib/libcurl${stdenv.hostPlatform.extensions.sharedLibrary} > $out/LibcurlPathFile
+  '';
+
+in
+
+stdenv.mkDerivation rec {
+  pname = "ldc";
+  inherit version;
+
+  src = fetchurl {
+    url = "https://github.com/ldc-developers/ldc/releases/download/v${version}/ldc-${version}-src.tar.gz";
+    inherit sha256;
+  };
+
+  # https://issues.dlang.org/show_bug.cgi?id=19553
+  hardeningDisable = [ "fortify" ];
+
+  postUnpack = ''
+    patchShebangs .
+  ''
+  + ''
+      rm ldc-${version}-src/tests/dmd/fail_compilation/mixin_gc.d
+      rm ldc-${version}-src/tests/dmd/runnable/xtest46_gc.d
+      rm ldc-${version}-src/tests/dmd/runnable/testptrref_gc.d
+
+      # test depends on current year
+      rm ldc-${version}-src/tests/dmd/compilable/ddocYear.d
+  ''
+  + lib.optionalString stdenv.hostPlatform.isDarwin ''
+      # https://github.com/NixOS/nixpkgs/issues/34817
+      rm -r ldc-${version}-src/tests/plugins/addFuncEntryCall
+  '';
+
+  postPatch = ''
+    # Setting SHELL=$SHELL when dmd testsuite is run doesn't work on Linux somehow
+    substituteInPlace tests/dmd/Makefile --replace "SHELL=/bin/bash" "SHELL=${bash}/bin/bash"
+  ''
+  + lib.optionalString stdenv.hostPlatform.isLinux ''
+      substituteInPlace runtime/phobos/std/socket.d --replace "assert(ih.addrList[0] == 0x7F_00_00_01);" ""
+  ''
+  + lib.optionalString stdenv.hostPlatform.isDarwin ''
+      substituteInPlace runtime/phobos/std/socket.d --replace "foreach (name; names)" "names = []; foreach (name; names)"
+  '';
+
+  nativeBuildInputs = [
+    cmake ldcBootstrap lit lit.python llvm_14.dev makeWrapper ninja unzip
+  ]
+  ++ lib.optionals stdenv.hostPlatform.isDarwin [
+    darwin.apple_sdk.frameworks.Foundation
+  ]
+  ++ lib.optionals (!stdenv.hostPlatform.isDarwin) [
+    # https://github.com/NixOS/nixpkgs/pull/36378#issuecomment-385034818
+    gdb
+  ];
+
+  buildInputs = [ curl tzdata ];
+
+  cmakeFlags = [
+    "-DD_FLAGS=-d-version=TZDatabaseDir;-d-version=LibcurlPath;-J${pathConfig}"
+    "-DCMAKE_BUILD_TYPE=Release"
+  ];
+
+  postConfigure = ''
+    export DMD=$PWD/bin/ldmd2
+  '';
+
+  makeFlags = [ "DMD=$DMD" ];
+
+  fixNames = lib.optionalString stdenv.hostPlatform.isDarwin  ''
+    fixDarwinDylibNames() {
+      local flags=()
+
+      for fn in "$@"; do
+        flags+=(-change "$(basename "$fn")" "$fn")
+      done
+
+      for fn in "$@"; do
+        if [ -L "$fn" ]; then continue; fi
+        echo "$fn: fixing dylib"
+        install_name_tool -id "$fn" "''${flags[@]}" "$fn"
+      done
+    }
+
+    fixDarwinDylibNames $(find "$(pwd)/lib" -name "*.dylib")
+    export DYLD_LIBRARY_PATH=$(pwd)/lib
+  '';
+
+  # https://github.com/ldc-developers/ldc/issues/2497#issuecomment-459633746
+  additionalExceptions = lib.optionalString stdenv.hostPlatform.isDarwin
+    "|druntime-test-shared";
+
+  checkPhase = ''
+    # Build default lib test runners
+    ninja -j$NIX_BUILD_CORES all-test-runners
+
+    ${fixNames}
+
+    # Run dmd testsuite
+    export DMD_TESTSUITE_MAKE_ARGS="-j$NIX_BUILD_CORES DMD=$DMD"
+    ctest -V -R "dmd-testsuite"
+
+    # Build and run LDC D unittests.
+    ctest --output-on-failure -R "ldc2-unittest"
+
+    # Run LIT testsuite.
+    ctest -V -R "lit-tests"
+
+    # Run default lib unittests
+    ctest -j$NIX_BUILD_CORES --output-on-failure -E "ldc2-unittest|lit-tests|dmd-testsuite${additionalExceptions}"
+  '';
+
+  postInstall = ''
+    wrapProgram $out/bin/ldc2 \
+        --prefix PATH ":" "${targetPackages.stdenv.cc}/bin" \
+        --set-default CC "${targetPackages.stdenv.cc}/bin/cc"
+   '';
+
+  meta = with lib; {
+    description = "The LLVM-based D compiler";
+    homepage = "https://github.com/ldc-developers/ldc";
+    # from https://github.com/ldc-developers/ldc/blob/master/LICENSE
+    license = with licenses; [ bsd3 boost mit ncsa gpl2Plus ];
+    maintainers = with maintainers; [ ThomasMader lionello ];
+    platforms = [ "x86_64-linux" "i686-linux" "aarch64-linux" "x86_64-darwin" "aarch64-darwin" ];
+  };
+}
+#+END_SRC
+
+**** bootstrap.nix
+
+#+HEADER: :tangle "../nix-overlays/ldc/bootstrap.nix"
+#+BEGIN_SRC nix
+<<ldc_bootstrap_1-25-0>>
+#+END_SRC
+
+#+NAME: ldc_bootstrap_1-25-0
+#+BEGIN_SRC nix
+{ callPackage }:
+callPackage ./binary.nix {
+  version = "1.25.0";
+  hashes = {
+    # Get these from `nix-prefetch-url https://github.com/ldc-developers/ldc/releases/download/v1.19.0/ldc2-1.19.0-osx-x86_64.tar.xz` etc..
+    osx-x86_64 = "sha256-6iKnbS+oalLKmyS8qYD/wS21b7+O+VgsWG2iT4PrWPU=";
+    linux-x86_64 = "sha256-sfg47RdlsIpryc3iZvE17OtLweh3Zw6DeuNJYgpuH+o=";
+    linux-aarch64  = "sha256-UDZ43x4flSo+SfsPeE8juZO2Wtk2ZzwySk0ADHnvJBI=";
+    osx-arm64  = "sha256-O/x0vy0wwQFaDc4uWSeMhx+chJKqbQb6e5QNYf+7DCw=";
+  };
+}
+#+END_SRC
+
+#+NAME: ldc_bootstrap_1-30-0
+#+BEGIN_SRC nix
+{ callPackage }:
+callPackage ./binary.nix {
+  version = "1.30.0";
+  hashes = {
+    # Get these from `nix store prefetch-file https://github.com/ldc-developers/ldc/releases/download/v1.19.0/ldc2-1.19.0-osx-x86_64.tar.xz` etc..
+    osx-x86_64 = "sha256-AAWZvxuZC82xvrW6fpYm783TY+H8k3DvqE94ZF1yjmk=";
+    linux-x86_64 = "sha256-V4TUzEfQhFrwiX07dHOgjdAoGkzausCkhnQIQNAU/eE=";
+    linux-aarch64  = "sha256-kTeglub75iv/jWWNPCn15aCGAbmck0RQl6L7bFOUu7Y=";
+    osx-arm64  = "sha256-Nb/owBdIeroB9jLMDvwjo8bvsTC9vFyJPLMTOMsSAd4=";
+  };
+}
+#+END_SRC
+
+- this is the ldc bootstrap in current use, nixpkgs:
+
+#+BEGIN_SRC nix
+{ callPackage }:
+callPackage ./binary.nix {
+  version = "1.30.0";
+  hashes = {
+    # Get these from `nix store prefetch-file https://github.com/ldc-developers/ldc/releases/download/v1.19.0/ldc2-1.19.0-osx-x86_64.tar.xz` etc..
+    osx-x86_64 = "sha256-AAWZvxuZC82xvrW6fpYm783TY+H8k3DvqE94ZF1yjmk=";
+    linux-x86_64 = "sha256-V4TUzEfQhFrwiX07dHOgjdAoGkzausCkhnQIQNAU/eE=";
+    linux-aarch64  = "sha256-kTeglub75iv/jWWNPCn15aCGAbmck0RQl6L7bFOUu7Y=";
+    osx-arm64  = "sha256-Nb/owBdIeroB9jLMDvwjo8bvsTC9vFyJPLMTOMsSAd4=";
+  };
+}
+#+END_SRC
+
+**** binary.nix (unaltered)
+
+#+HEADER: :tangle "../nix-overlays/ldc/binary.nix"
+#+BEGIN_SRC nix
+{ lib, stdenv, fetchurl, curl, tzdata, autoPatchelfHook, fixDarwinDylibNames, libxml2
+, version, hashes }:
+
+let
+  inherit (stdenv) hostPlatform;
+  OS = if hostPlatform.isDarwin then "osx" else hostPlatform.parsed.kernel.name;
+  ARCH = if hostPlatform.isDarwin && hostPlatform.isAarch64 then "arm64" else hostPlatform.parsed.cpu.name;
+in stdenv.mkDerivation {
+  pname = "ldc-bootstrap";
+  inherit version;
+
+  src = fetchurl rec {
+    name = "ldc2-${version}-${OS}-${ARCH}.tar.xz";
+    url = "https://github.com/ldc-developers/ldc/releases/download/v${version}/${name}";
+    sha256 = hashes."${OS}-${ARCH}" or (throw "missing bootstrap sha256 for ${OS}-${ARCH}");
+  };
+
+  dontConfigure = true;
+  dontBuild = true;
+
+  nativeBuildInputs = lib.optionals hostPlatform.isLinux [
+    autoPatchelfHook
+  ] ++ lib.optional hostPlatform.isDarwin fixDarwinDylibNames;
+
+  buildInputs = lib.optionals stdenv.hostPlatform.isLinux [ libxml2 stdenv.cc.cc ];
+
+  propagatedBuildInputs = [ curl tzdata ];
+
+  installPhase = ''
+    mkdir -p $out
+
+    mv bin etc import lib LICENSE README $out/
+  '';
+
+  meta = with lib; {
+    description = "The LLVM-based D Compiler";
+    homepage = "https://github.com/ldc-developers/ldc";
+    # from https://github.com/ldc-developers/ldc/blob/master/LICENSE
+    license = with licenses; [ bsd3 boost mit ncsa gpl2Plus ];
+    maintainers = with maintainers; [ ThomasMader lionello ];
+    platforms = [ "x86_64-linux" "x86_64-darwin" "aarch64-linux" "aarch64-darwin" ];
+  };
+}
+#+END_SRC
+
+*** versions SET
+**** selected version SET OK ✓
+***** version & sha256 nix composite
+
+#+NAME: ldc_version_info
+#+BEGIN_SRC nix
+version = "<<ldc_version>>";
+sha256 = "<<ldc_hash>>";
+#+END_SRC
+
+***** select version SET OK ✓
+
+#+NAME: ldc_version
+#+BEGIN_SRC nix
+<<ldc_version_1_33_0-beta1>>
+#+END_SRC
+
+#+NAME: ldc_hash
+#+BEGIN_SRC nix
+<<ldc_hash_1_33_0-beta1>>
+#+END_SRC
+
+**** 1.33.0-beta1
+
+- nix-prefetch-url --unpack https://github.com/ldc-developers/ldc/archive/refs/tags/v1.32.1.tar.gz
+
+#+NAME: ldc_version_1_33_0-beta1
+#+BEGIN_SRC nix
+1.33.0-beta1
+#+END_SRC
+
+#+NAME: ldc_hash_1_33_0-beta1
+#+BEGIN_SRC nix
+sha256-axyjDAWwxHmG2yPhL6P8cF6XvVvapfw0AWLjUrVRoug=
+#+END_SRC
+
+**** 1.32.2 OK ✓
+
+- nix-prefetch-url --unpack https://github.com/ldc-developers/ldc/archive/refs/tags/v1.32.1.tar.gz
+
+#+NAME: ldc_version_1_32_2
+#+BEGIN_SRC nix
+1.32.2
+#+END_SRC
+
+#+NAME: ldc_hash_1_32_2
+#+BEGIN_SRC nix
+sha256-v6Sq7nQyChJohDyI4inzObLfCVOkvLT87VLr4N2hzZU=
+#+END_SRC
+
+**** 1.32.1
+
+- nix-prefetch-url --unpack https://github.com/ldc-developers/ldc/archive/refs/tags/v1.32.1.tar.gz
+
+#+NAME: ldc_version_1_32_1
+#+BEGIN_SRC nix
+1.32.1
+#+END_SRC
+
+#+NAME: ldc_hash_1_32_1
+#+BEGIN_SRC nix
+sha256-s1U7+qiVJDF+zSHrLGPG6g+acIChYnXkb9p+OrNX6g8=
+#+END_SRC
+
+**** 1.32.0
+
+- nix-prefetch-url --unpack https://github.com/ldc-developers/ldc/archive/refs/tags/v1.32.0.tar.gz
+
+#+NAME: ldc_version_1_32_0
+#+BEGIN_SRC nix
+1.32.0
+#+END_SRC
+
+#+NAME: ldc_hash_1_32_0
+#+BEGIN_SRC nix
+sha256-xO4L+RtBbdVkE1PZsme2pIYAxJnHgr6xEtLkYOMpvqw=
+#+END_SRC
+
+**** 1.31.0
+
+- nix-prefetch-url --unpack https://github.com/ldc-developers/ldc/archive/refs/tags/v1.31.0.tar.gz
+
+#+NAME: ldc_version_1_31_0
+#+BEGIN_SRC nix
+1.31.0
+#+END_SRC
+
+#+NAME: ldc_hash_1_31_0
+#+BEGIN_SRC nix
+sha256-8cjs6eHjWAbDRBvyT75mbN3Y7vN1WSwZzY/uRwHNVFg=
+#+END_SRC
+
+**** 1.30.0
+
+- nix-prefetch-url --unpack https://github.com/ldc-developers/ldc/archive/refs/tags/v1.30.0.tar.gz
+
+#+NAME: ldc_version_1_30_0
+#+BEGIN_SRC nix
+1.30.0
+#+END_SRC
+
+#+NAME: ldc_hash_1_30_0
+#+BEGIN_SRC nix
+sha256-/bs3bwgkLZF5IqaiKnc5gCF/r6MQBG/F1kWUkK8j2s0=
+#+END_SRC
+
+** dmd OK KO ✗ ISSUES
+*** info
+**** links
+
+- https://dlang.org/
+  - https://wiki.dlang.org/LDC
+
+- https://github.com/dlang/dmd
+  - https://github.com/dlang/dmd/tags
+  - https://github.com/dlang/dmd/pulls
+
+- version in nixpkgs:
+  - https://search.nixos.org/packages?channel=unstable&show=dmd&from=0&size=100&sort=relevance&type=packages&query=dmd
+
+**** notes KO ✗
+
+- dmd nixpkg modified and appears to build ok
+
+- ISSUES dmd on nixos FAILS to build (my working projects), appears not to find parts of itself
+
+*** overlays
+**** default.nix
+
+#+HEADER: :tangle "../nix-overlays/dmd/default.nix"
+#+BEGIN_SRC nix
+import ./generic.nix {
+  version = "<<dmd_version>>";
+  dmdSha256 = "<<dmd_hash>>";
+  #druntimeSha256 = "<<druntime_hash>>";
+  phobosSha256 = "<<phobos_hash>>";
+}
+#+END_SRC
+
+**** generic.nix
+
+#+HEADER: :tangle "../nix-overlays/dmd/generic.nix"
+#+BEGIN_SRC nix
+{ version
+, dmdSha256
+, phobosSha256
+}:
+
+{ stdenv
+, lib
+, fetchFromGitHub
+, makeWrapper
+, which
+, writeTextFile
+, curl
+, tzdata
+, gdb
+, callPackage
+, targetPackages
+, fetchpatch
+, bash
+, installShellFiles
+, git
+, unzip
+, HOST_DMD ? "${callPackage ./bootstrap.nix { }}/bin/dmd"
+}:
+
+let
+  dmdConfFile = writeTextFile {
+    name = "dmd.conf";
+    text = (lib.generators.toINI { } {
+      Environment = {
+        DFLAGS = ''-I@out@/include/dmd -L-L@out@/lib -fPIC ${lib.optionalString (!targetPackages.stdenv.cc.isClang) "-L--export-dynamic"}'';
+      };
+    });
+  };
+
+  bits = builtins.toString stdenv.hostPlatform.parsed.cpu.bits;
+  osname =
+    if stdenv.isDarwin then
+      "osx"
+    else
+      stdenv.hostPlatform.parsed.kernel.name;
+
+  pathToDmd = "\${NIX_BUILD_TOP}/dmd/generated/${osname}/release/${bits}/dmd";
+in
+
+stdenv.mkDerivation rec {
+  pname = "dmd";
+  inherit version;
+
+  enableParallelBuilding = true;
+
+  srcs = [
+    (fetchFromGitHub {
+      owner = "dlang";
+      repo = "dmd";
+      rev = "v${version}";
+      sha256 = dmdSha256;
+      name = "dmd";
+    })
+    (fetchFromGitHub {
+      owner = "dlang";
+      repo = "phobos";
+      rev = "v${version}";
+      sha256 = phobosSha256;
+      name = "phobos";
+    })
+  ];
+
+  sourceRoot = ".";
+
+  # https://issues.dlang.org/show_bug.cgi?id=19553
+  hardeningDisable = [ "fortify" ];
+
+  #patches = lib.optionals (lib.versionOlder version "2.088.0") [
+  #  # Migrates D1-style operator overloads in DMD source, to allow building with
+  #  # a newer DMD
+  #  (fetchpatch {
+  #    url = "https://github.com/dlang/dmd/commit/c4d33e5eb46c123761ac501e8c52f33850483a8a.patch";
+  #    stripLen = 1;
+  #    extraPrefix = "dmd/";
+  #    sha256 = "sha256-N21mAPfaTo+zGCip4njejasraV5IsWVqlGR5eOdFZZE=";
+  #  })
+  #] ++ lib.optionals (lib.versionOlder version "2.092.2") [
+  #  # Fixes C++ tests that compiled on older C++ but not on the current one
+  #  (fetchpatch {
+  #    url = "https://github.com/dlang/druntime/commit/438990def7e377ca1f87b6d28246673bb38022ab.patch";
+  #    stripLen = 1;
+  #    extraPrefix = "druntime/";
+  #    sha256 = "sha256-/pPKK7ZK9E/mBrxm2MZyBNhYExE8p9jz8JqBdZSE6uY=";
+  #  })
+  #];
+
+  postPatch = ''
+    patchShebangs dmd/compiler/test/{runnable,fail_compilation,compilable,tools}{,/extra-files}/*.sh
+
+    rm dmd/compiler/test/runnable_cxx/cppa.d
+
+    # Grep'd string changed with gdb 12
+    #   https://issues.dlang.org/show_bug.cgi?id=23198
+    substituteInPlace dmd/druntime/test/exceptions/Makefile \
+      --replace 'in D main (' 'in _Dmain ('
+
+    # We're using gnused on all platforms
+    substituteInPlace dmd/druntime/test/coverage/Makefile \
+      --replace 'freebsd osx' 'none'
+  ''
+
+  + lib.optionalString (lib.versionOlder version "2.091.0") ''
+    # This one has tested against a hardcoded year, then against a current year on
+    # and off again. It just isn't worth it to patch all the historical versions
+    # of it, so just remove it until the most recent change.
+    rm dmd/compiler/test/compilable/ddocYear.d
+  '' + lib.optionalString (lib.versionAtLeast version "2.089.0" && lib.versionOlder version "2.092.2") ''
+    rm dmd/compiler/test/dshell/test6952.d
+  '' + lib.optionalString (lib.versionAtLeast version "2.092.2") ''
+    substituteInPlace dmd/compiler/test/dshell/test6952.d --replace "/usr/bin/env bash" "${bash}/bin/bash"
+  ''
+
+  + lib.optionalString stdenv.isLinux ''
+    substituteInPlace phobos/std/socket.d --replace "assert(ih.addrList[0] == 0x7F_00_00_01);" ""
+  '' + lib.optionalString stdenv.isDarwin ''
+    substituteInPlace phobos/std/socket.d --replace "foreach (name; names)" "names = []; foreach (name; names)"
+  '';
+
+  nativeBuildInputs = [
+    makeWrapper
+    which
+    installShellFiles
+  ] ++ lib.optionals (lib.versionOlder version "2.088.0") [
+    git
+  ];
+
+  buildInputs = [
+    curl
+    tzdata
+  ];
+
+  nativeCheckInputs = [
+    gdb
+  ] ++ lib.optionals (lib.versionOlder version "2.089.0") [
+    unzip
+  ];
+
+  buildFlags = [
+    "BUILD=release"
+    "ENABLE_RELEASE=1"
+    "PIC=1"
+  ];
+
+  # Build and install are based on http://wiki.dlang.org/Building_DMD
+  buildPhase = ''
+    runHook preBuild
+
+    export buildJobs=$NIX_BUILD_CORES
+    if [ -z $enableParallelBuilding ]; then
+      buildJobs=1
+    fi
+
+    make -C dmd -f posix.mak $buildFlags -j$buildJobs HOST_DMD=${HOST_DMD}
+    echo ${tzdata}/share/zoneinfo/ > TZDatabaseDirFile
+    echo ${lib.getLib curl}/lib/libcurl${stdenv.hostPlatform.extensions.sharedLibrary} > LibcurlPathFile
+    make -C phobos -f posix.mak $buildFlags -j$buildJobs DMD=${pathToDmd} DFLAGS="-version=TZDatabaseDir -version=LibcurlPath -J$PWD"
+
+    runHook postBuild
+  '';
+
+  doCheck = true;
+
+  checkFlags = buildFlags;
+
+  # many tests are disbled because they are failing
+
+  # NOTE: Purity check is disabled for checkPhase because it doesn't fare well
+  # with the DMD linker. See https://github.com/NixOS/nixpkgs/issues/97420
+  checkPhase = ''
+    runHook preCheck
+
+    export checkJobs=$NIX_BUILD_CORES
+    if [ -z $enableParallelChecking ]; then
+      checkJobs=1
+    fi
+
+    NIX_ENFORCE_PURITY= \
+      make -C dmd/compiler/test $checkFlags CC=$CXX SHELL=$SHELL -j$checkJobs N=$checkJobs
+
+    NIX_ENFORCE_PURITY= \
+      make -C phobos -f posix.mak unittest $checkFlags -j$checkJobs DFLAGS="-version=TZDatabaseDir -version=LibcurlPath -J$PWD"
+
+    runHook postCheck
+  '';
+
+  installPhase = ''
+    runHook preInstall
+
+    install -Dm755 ${pathToDmd} $out/bin/dmd
+
+    installManPage dmd/docs/man/man*/*
+
+    mkdir $out/lib
+    cp phobos/generated/${osname}/release/${bits}/libphobos2.* $out/lib/
+
+    wrapProgram $out/bin/dmd \
+      --prefix PATH ":" "${targetPackages.stdenv.cc}/bin" \
+      --set-default CC "${targetPackages.stdenv.cc}/bin/cc"
+
+    substitute ${dmdConfFile} "$out/bin/dmd.conf" --subst-var out
+
+    runHook postInstall
+  '';
+
+  meta = with lib; {
+    description = "Official reference compiler for the D language";
+    homepage = "https://dlang.org/";
+    # Everything is now Boost licensed, even the backend.
+    # https://github.com/dlang/dmd/pull/6680
+    license = licenses.boost;
+    maintainers = with maintainers; [ ThomasMader lionello dukc ];
+    platforms = [ "x86_64-linux" "i686-linux" "x86_64-darwin" ];
+  };
+}
+#+END_SRC
+
+**** bootstrap.nix
+
+#+HEADER: :tangle "../nix-overlays/dmd/bootstrap.nix"
+#+BEGIN_SRC nix
+{ callPackage }:
+callPackage ./binary.nix {
+  version = "2.090.1";
+  hashes = {
+    # Get these from `nix-prefetch-url http://downloads.dlang.org/releases/2.x/2.090.1/dmd.2.090.1.linux.tar.xz` etc..
+    osx = "sha256-9HwGVO/8jfZ6aTiDIUi8w4C4Ukry0uUS8ACP3Ig8dmU=";
+    linux = "sha256-ByCrIA4Nt7i9YT0L19VXIL1IqIp+iObcZux407amZu4=";
+  };
+}
+#+END_SRC
+
+**** binary.nix
+
+#+HEADER: :tangle "../nix-overlays/dmd/binary.nix"
+#+BEGIN_SRC nix
+{ lib, stdenv, fetchurl, curl, tzdata, autoPatchelfHook, fixDarwinDylibNames, glibc
+, version, hashes }:
+
+let
+  inherit (stdenv) hostPlatform;
+  OS = if hostPlatform.isDarwin then "osx" else hostPlatform.parsed.kernel.name;
+  MODEL = toString hostPlatform.parsed.cpu.bits;
+in stdenv.mkDerivation {
+  pname = "dmd-bootstrap";
+  inherit version;
+
+  src = fetchurl rec {
+    name = "dmd.${version}.${OS}.tar.xz";
+    url = "http://downloads.dlang.org/releases/2.x/${version}/${name}";
+    sha256 = hashes.${OS} or (throw "missing bootstrap sha256 for OS ${OS}");
+  };
+
+  dontConfigure = true;
+  dontBuild = true;
+
+  nativeBuildInputs = lib.optionals hostPlatform.isLinux [
+    autoPatchelfHook
+  ] ++ lib.optionals hostPlatform.isDarwin [
+    fixDarwinDylibNames
+  ];
+  propagatedBuildInputs = [
+    curl
+    tzdata
+  ] ++ lib.optionals hostPlatform.isLinux [
+    glibc
+    stdenv.cc.cc.libgcc
+  ];
+
+  installPhase = ''
+    runHook preInstall
+
+    mkdir -p $out
+
+    # try to copy model-specific binaries into bin first
+    mv ${OS}/bin${MODEL} $out/bin || true
+
+    mv src license.txt ${OS}/* $out/
+
+    # move man into place
+    mkdir -p $out/share
+    mv man $out/share/
+
+    # move docs into place
+    mkdir -p $out/share/doc
+    mv html/d $out/share/doc/
+
+    # fix paths in dmd.conf (one level less)
+    substituteInPlace $out/bin/dmd.conf --replace "/../../" "/../"
+
+    runHook postInstall
+  '';
+
+  # Stripping on Darwin started to break libphobos2.a
+  # Undefined symbols for architecture x86_64:
+  #   "_rt_envvars_enabled", referenced from:
+  #       __D2rt6config16rt_envvarsOptionFNbNiAyaMDFNbNiQkZQnZQq in libphobos2.a(config_99a_6c3.o)
+  dontStrip = hostPlatform.isDarwin;
+
+  meta = with lib; {
+    description = "Digital Mars D Compiler Package";
+    # As of 2.075 all sources and binaries use the boost license
+    license = licenses.boost;
+    maintainers = [ maintainers.lionello ];
+    homepage = "https://dlang.org/";
+    platforms = [ "x86_64-darwin" "i686-linux" "x86_64-linux" ];
+  };
+}
+#+END_SRC
+
+*** versions SET
+**** selected version SET KO ✗
+
+#+NAME: dmd_version
+#+BEGIN_SRC nix
+<<dmd_version_2_104_0>>
+#+END_SRC
+
+#+NAME: dmd_hash
+#+BEGIN_SRC nix
+<<dmd_hash_2_104_0>>
+#+END_SRC
+
+#+NAME: phobos_hash
+#+BEGIN_SRC nix
+<<phobos_hash_2_104_0>>
+#+END_SRC
+
+**** 2.104.0 KO ✗
+
+- nix-prefetch-url --unpack https://github.com/dlang/dmd/archive/refs/tags/v2.104.0.tar.gz
+- nix-prefetch-url --unpack https://github.com/dlang/phobos/archive/refs/tags/v2.104.0.tar.gz
+
+#+NAME: dmd_version_2_104_0
+#+BEGIN_SRC nix
+2.104.0
+#+END_SRC
+
+#+NAME: dmd_hash_2_104_0
+#+BEGIN_SRC nix
+sha256-yv+uW6cYAId2HK/YSPxsR9Xt0o3LWa97z8KyzjFik6s=
+#+END_SRC
+
+#+NAME: phobos_hash_2_104_0
+#+BEGIN_SRC nix
+sha256-cWp36Gd/lh3gy21bf9z0/RqzlJmf6ypmx72aMeakcec=
+#+END_SRC
+
+**** 2.102.2 KO ✗
+
+- nix-prefetch-url --unpack https://github.com/dlang/dmd/archive/refs/tags/v2.102.2.tar.gz
+- nix-prefetch-url --unpack https://github.com/dlang/phobos/archive/refs/tags/v2.102.2.tar.gz
+
+#+NAME: dmd_version_2_102_2
+#+BEGIN_SRC nix
+2.102.2
+#+END_SRC
+
+#+NAME: dmd_hash_2_102_2
+#+BEGIN_SRC nix
+sha256-der9nb31hJ+K1aJZdzIgs8+eRgVVsH97QnYEnVbKUws=
+#+END_SRC
+
+#+NAME: phobos_hash_2_102_2
+#+BEGIN_SRC nix
+sha256-SracmUm2aY/LDCyDqYuVS39pCbwO8UCL3TSB0CVHpHE=
+#+END_SRC
+
+**** 2.100.2 KO ✗
+
+- nix-prefetch-url --unpack https://github.com/dlang/dmd/archive/refs/tags/v2.100.2.tar.gz
+- nix-prefetch-url --unpack https://github.com/dlang/druntime/archive/refs/tags/v2.100.2.tar.gz
+- nix-prefetch-url --unpack https://github.com/dlang/phobos/archive/refs/tags/v2.100.2.tar.gz
+
+#+NAME: dmd_version_2_100_2
+#+BEGIN_SRC nix
+2.100.2
+#+END_SRC
+
+#+NAME: dmd_hash_2_100_2
+#+BEGIN_SRC nix
+sha256-o4+G3ARXIGObYHtHooYZKr+Al6kHpiwpMIog3i4BlDM=
+#+END_SRC
+
+#+NAME: druntime_hash_2_100_2
+#+BEGIN_SRC nix
+sha256-qXvY1ECN4mPwOGgOE1FWwvxoRvlSww3tGLWgBdhzAKo=
+#+END_SRC
+
+#+NAME: phobos_hash_2_100_2
+#+BEGIN_SRC nix
+sha256-kTHRaAKG7cAGb4IE/NGHWaZ8t7ZceKj03l6E8wLzJzs=
+#+END_SRC
+
+** dub OK KO ✗ ISSUE (>= 1.31.0)
+*** info
+**** links
+
+- https://code.dlang.org/packages/dub
+
+- https://github.com/dlang/dub
+  - https://github.com/dlang/dub/releases
+  - https://github.com/dlang/dub/issues
+
+- version in nixpkgs:
+  - https://search.nixos.org/packages?channel=unstable&show=dub&from=0&size=100&sort=relevance&type=packages&query=dub
+
+**** notes
+
+- OK dub == 1.30.0 OK ✓
+
+- NOTES for dub >= 1.31.0 KO ✗
+  - dub builds test tilix which calls in gtkd
+  - ISSUES dub FAILS to build project from local disk that has built without issue
+    since dub v1.23.0
+    - BROKEN breaks on subproject ends up in nix: Error /homeless-shelter:
+      Permission denied
+
+*** overlays
+**** default.nix OK ✓
+
+#+HEADER: :tangle "../nix-overlays/dub/default.nix"
+#+BEGIN_SRC nix
+{ lib, stdenv, fetchFromGitHub, curl, libevent, rsync, ldc, dcompiler ? ldc }:
+
+assert dcompiler != null;
+
+stdenv.mkDerivation rec {
+  pname = "dub";
+  version = "<<dub_version>>";
+
+  enableParallelBuilding = true;
+
+  src = fetchFromGitHub {
+    owner = "dlang";
+    repo = "dub";
+    rev = "v${version}";
+    sha256 = "<<dub_hash>>";
+  };
+
+  #postUnpack = ''
+  #  patchShebangs .
+  #'';
+
+  dubvar = "\\$DUB";
+  postPatch = ''
+    patchShebangs test
+
+    # Can be removed with https://github.com/dlang/dub/pull/1368
+    substituteInPlace test/fetchzip.sh \
+        --replace "dub remove" "\"${dubvar}\" remove"
+  '';
+
+  nativeBuildInputs = [ dcompiler libevent rsync ];
+  buildInputs = [ curl ];
+
+  buildPhase = ''
+    for DC_ in dmd ldmd2 gdmd; do
+      echo "... check for D compiler $DC_ ..."
+      export DC=$(type -P $DC_ || echo "")
+      if [ ! "$DC" == "" ]; then
+        break
+      fi
+    done
+    if [ "$DC" == "" ]; then
+      exit "Error: could not find D compiler"
+    fi
+    echo "$DC_ found and used as D compiler in buildPhase for $pname"
+    $DC ./build.d
+    ./build
+  '';
+
+  doCheck = !stdenv.isDarwin;
+
+  checkPhase = ''
+    export DUB=$NIX_BUILD_TOP/source/bin/dub
+    export PATH=$PATH:$NIX_BUILD_TOP/source/bin/
+    #export DC=${dcompiler.out}/bin/${if dcompiler.pname=="ldc" then "ldc2" else dcompiler.pname}
+    if [ "$DC" == "" ]; then
+      exit "Error: could not find D compiler"
+    fi
+    echo "DC out --> $DC"
+    export HOME=$TMP
+
+    rm -rf test/issue502-root-import
+    rm -rf test/dpath-variable
+    rm test/dpath-variable.sh
+    rm -rf test/git-dependency
+    rm -rf test/use-c-sources # added to build v1.33.0
+
+    ./test/run-unittest.sh
+  '';
+
+  installPhase = ''
+    mkdir -p $out/bin
+    cp bin/dub $out/bin
+  '';
+
+  meta = with lib; {
+    description = "Package and build manager for D applications and libraries";
+    homepage = "https://code.dlang.org/";
+    license = licenses.mit;
+    maintainers = with maintainers; [ ThomasMader ];
+    platforms = [ "x86_64-linux" "i686-linux" "aarch64-linux" "x86_64-darwin" "aarch64-darwin" ];
+  };
+}
+#+END_SRC
+
+*** versions SET
+**** selected version SET
+
+#+NAME: dub_version
+#+BEGIN_SRC nix
+<<dub_version_1_30_0>>
+#+END_SRC
+
+#+NAME: dub_hash
+#+BEGIN_SRC nix
+<<dub_hash_1_30_0>>
+#+END_SRC
+
+**** 1.33.0 OK ✓ KO ✗ ISSUE
+
+- nix-prefetch-url --unpack https://github.com/dlang/dub/archive/refs/tags/v1.33.0.tar.gz
+
+#+NAME: dub_version_1_33_0
+#+BEGIN_SRC nix
+1.33.0
+#+END_SRC
+
+#+NAME: dub_hash_1_33_0
+#+BEGIN_SRC nix
+sha256-4Mha7WF6cg3DIccfpvOnheuvgfziv/7wo8iFsPXO4yY=
+#+END_SRC
+
+**** 1.32.1 OK ✓ KO ✗ ISSUE
+
+- nix-prefetch-url --unpack https://github.com/dlang/dub/archive/refs/tags/v1.32.1.tar.gz
+
+#+NAME: dub_version_1_32_1
+#+BEGIN_SRC nix
+1.32.1
+#+END_SRC
+
+#+NAME: dub_hash_1_32_1
+#+BEGIN_SRC nix
+sha256-5pW3Fu3PQ1ZLJnsuh7fPpEBNbVQgGfFyiuMrAVOJKQA=
+#+END_SRC
+
+- ISSUES from 1.31.0 continuing
+
+**** 1.31.1 OK ✓ KO ✗ ISSUE
+
+- nix-prefetch-url --unpack https://github.com/dlang/dub/archive/refs/tags/v1.31.1.tar.gz
+
+#+NAME: dub_version_1_31_1
+#+BEGIN_SRC nix
+1.31.1
+#+END_SRC
+
+#+NAME: dub_hash_1_31_1
+#+BEGIN_SRC nix
+sha256-dp64D51ypowXS1+EYKRXh5hpa3rMmiotvKO2FW+i92w=
+#+END_SRC
+
+- ISSUES from 1.31.0 continuing
+
+**** 1.31.0 OK ✓ KO ✗ ISSUE
+
+- nix-prefetch-url --unpack https://github.com/dlang/dub/archive/refs/tags/v1.31.0.tar.gz
+
+#+NAME: dub_version_1_31_0
+#+BEGIN_SRC nix
+1.31.0
+#+END_SRC
+
+#+NAME: dub_hash_1_31_0
+#+BEGIN_SRC nix
+sha256-Ki8HJOfWFM1tF86s7Ng3STgC/uu5acVTP0Dj87M0l54=
+#+END_SRC
+
+- ISSUES from 1.31.0 continuing
+**** 1.30.0 OK ✓
+
+- nix-prefetch-url --unpack https://github.com/dlang/dub/archive/refs/tags/v1.30.0.tar.gz
+
+#+NAME: dub_version_1_30_0
+#+BEGIN_SRC nix
+1.30.0
+#+END_SRC
+
+#+NAME: dub_hash_1_30_0
+#+BEGIN_SRC nix
+sha256-iVl7bjblvIxvrUX7Phq6h4AIAmZjNVkGYYFA1hhsE7c=
+#+END_SRC
+
+**** 1.29.1
+
+- nix-prefetch-url --unpack https://github.com/dlang/dub/archive/refs/tags/v1.29.1.tar.gz
+
+#+NAME: dub_version_1_29_1
+#+BEGIN_SRC nix
+1.29.1
+#+END_SRC
+
+#+NAME: dub_hash_1_29_1
+#+BEGIN_SRC nix
+sha256-XDV9p1bDhRL6gX+nizzjoErNJm8NnQK5O8wNnizloss=
+#+END_SRC
+
+**** 1.28.0
+
+- nix-prefetch-url --unpack https://github.com/dlang/dub/archive/refs/tags/v1.28.0.tar.gz
+
+#+NAME: dub_version_1_28_0
+#+BEGIN_SRC nix
+1.28.0
+#+END_SRC
+
+#+NAME: dub_hash_1_28_0
+#+BEGIN_SRC nix
+sha256-GOeaQyu8Y/DxZEAJPdlGH9ie/ZRTqvAw2jjvM3dESbg=
+#+END_SRC
+
+** dtools OK ✓
+*** info
+**** links
+
+- https://code.dlang.org/packages/dtools
+
+- https://github.com/dlang/tools
+  - https://github.com/dlang/tools/tags
+    nix-prefetch --unpack https://github.com/dlang/tools/archive/refs/tags/v<<dtools_version>>.tar.gz
+  - https://github.com/dlang/tools/issues
+
+- version in nixpkgs
+  - https://search.nixos.org/packages?channel=unstable&show=dtools&from=0&size=100&sort=relevance&type=packages&query=dtools
+
+**** notes
+
+- OK dtools 2.103.1
+
+*** overlays
+**** default.nix
+
+#+HEADER: :tangle "../nix-overlays/dtools/default.nix"
+#+BEGIN_SRC nix
+{ stdenv, lib, fetchFromGitHub, fetchpatch, ldc, curl, gnumake42 }:
+
+stdenv.mkDerivation rec {
+  pname = "dtools";
+  version = "<<dtools_version>>";
+
+  src = fetchFromGitHub {
+    owner = "dlang";
+    repo = "tools";
+    rev = "v${version}";
+    sha256 = "<<dtools_hash>>";
+    name = "dtools";
+  };
+
+  patches = [
+    (fetchpatch {
+      # part of https://github.com/dlang/tools/pull/441
+      url = "https://github.com/dlang/tools/commit/6c6a042d1b08e3ec1790bd07a7f69424625ee866.patch"; # Fix LDC arm64 build
+      sha256 = "sha256-x6EclTYN1Y5FG57KLhbBK0BZicSYcZoWO7MTVcP4T18=";
+    })
+  ];
+
+  nativeBuildInputs = [ ldc gnumake42 ]; # fails with make 4.4
+  buildInputs = [ curl ];
+
+  makeCmd = ''
+    make -f posix.mak all DMD_DIR=dmd DMD=${ldc.out}/bin/ldmd2 CC=${stdenv.cc}/bin/cc
+  '';
+
+  buildPhase = ''
+    $makeCmd
+  '';
+
+  doCheck = true;
+
+  checkPhase = ''
+      $makeCmd test_rdmd
+    '';
+
+  installPhase = ''
+      $makeCmd INSTALL_DIR=$out install
+  '';
+
+  meta = with lib; {
+    description = "Ancillary tools for the D programming language compiler";
+    homepage = "https://github.com/dlang/tools";
+    license = lib.licenses.boost;
+    maintainers = with maintainers; [ ThomasMader ];
+    platforms = lib.platforms.unix;
+  };
+}
+#+END_SRC
+
+*** versions SET
+
+- https://github.com/dlang/tools
+
+**** selected version SET OK ✓
+
+#+NAME: dtools_version
+#+BEGIN_SRC nix
+<<dtools_version_2_103_1>>
+#+END_SRC
+
+#+NAME: dtools_hash
+#+BEGIN_SRC nix
+<<dtools_hash_2_103_1>>
+#+END_SRC
+
+**** 2.103.1 OK ✓
+
+- https://github.com/dlang/tools/releases/tag/v2.103.1
+
+#+NAME: dtools_version_2_103_1
+#+BEGIN_SRC nix
+2.103.1
+#+END_SRC
+
+#+NAME: dtools_hash_2_103_1
+#+BEGIN_SRC nix
+sha256-XM4gUxcarQCOBR8W/o0iWAI54PyLDkH6CsDce22Cnu4=
+#+END_SRC
+
+**** 2.102.2
+
+- https://github.com/dlang/tools/releases/tag/v2.102.2
+
+#+NAME: dtools_version_2_102_2
+#+BEGIN_SRC nix
+2.102.2
+#+END_SRC
+
+#+NAME: dtools_hash_2_102_2
+#+BEGIN_SRC nix
+sha256-XM4gUxcarQCOBR8W/o0iWAI54PyLDkH6CsDce22Cnu4=
+#+END_SRC
+
+**** 2.095.1 current nixpkgs 20-03-17 OK ✓
+
+- https://github.com/dlang/tools/releases/tag/v2.095.1
+
+#+NAME: dtools_version_2_095_1
+#+BEGIN_SRC nix
+2.095.1
+#+END_SRC
+
+#+NAME: dtools_hash_2_095_1
+#+BEGIN_SRC nix
+sha256:0rdfk3mh3fjrb0h8pr8skwlq6ac9hdl1fkrkdl7n1fa2806b740b
+#+END_SRC
+
+** sha256 blank_hash
+
+#+NAME: blank_hash
+#+BEGIN_SRC nix
+sha256-0000000000000000000000000000000000000000000=
+#+END_SRC
+
+#+NAME: assumed_hash
+#+BEGIN_SRC nix
+sha256-AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=
+#+END_SRC