yosys: 0.38 -> 0.42

ABC is now included as a submodule, and we choose to build it like that
instead of having to maintain nixpkgs's version, as each version of Yosys
is only compatible with one particular version of ABC. The built ABC is
available in `$out/bin/yosys-abc` as before.

A little munging is required to present the git hashes as desired.

Additionally, some upstreamed patches are dropped.

pkgs/development/compilers/yosys/default.nix

@@ -1,6 +1,5 @@
 { stdenv
 , lib
-, abc-verifier
 , bash
 , bison
 , boost
@@ -77,13 +76,27 @@ let
 
 in stdenv.mkDerivation (finalAttrs: {
   pname   = "yosys";
-  version = "0.38";
+  version = "0.42";
 
   src = fetchFromGitHub {
     owner = "YosysHQ";
     repo  = "yosys";
     rev   = "refs/tags/${finalAttrs.pname}-${finalAttrs.version}";
-    hash  = "sha256-mzMBhnIEgToez6mGFOvO7zBA+rNivZ9OnLQsjBBDamA=";
+    hash  = "sha256-P0peg81wxCG0Bw2EJEX5WuDYU7GmRqgRw2SyWK/CGNI=";
+    fetchSubmodules = true;
+    leaveDotGit = true;
+    postFetch = ''
+      # set up git hashes as if we used the tarball
+
+      pushd $out
+      git rev-parse HEAD > .gitcommit
+      cd $out/abc
+      git rev-parse HEAD > .gitcommit
+      popd
+
+      # remove .git now that we are through with it
+      find "$out" -name .git -print0 | xargs -0 rm -rf
+    '';
   };
 
   enableParallelBuilding = true;
@@ -109,25 +122,13 @@ in stdenv.mkDerivation (finalAttrs: {
     substituteInPlace ./Makefile \
       --replace-fail 'echo UNKNOWN' 'echo ${builtins.substring 0 10 finalAttrs.src.rev}'
 
-    # https://github.com/YosysHQ/yosys/pull/4199
-    substituteInPlace ./tests/various/clk2fflogic_effects.sh \
-      --replace-fail 'tail +3' 'tail -n +3'
-
     chmod +x ./misc/yosys-config.in
     patchShebangs tests ./misc/yosys-config.in
   '';
 
-  preBuild = let
-    shortAbcRev = builtins.substring 0 7 abc-verifier.rev;
-  in ''
+  preBuild = ''
     chmod -R u+w .
     make config-${if stdenv.cc.isClang or false then "clang" else "gcc"}
-    echo 'ABCEXTERNAL = ${abc-verifier}/bin/abc' >> Makefile.conf
-
-    if ! grep -q "ABCREV = ${shortAbcRev}" Makefile; then
-      echo "ERROR: yosys isn't compatible with the provided abc (${shortAbcRev}), failing."
-      exit 1
-    fi
 
     if ! grep -q "YOSYS_VER := $version" Makefile; then
       echo "ERROR: yosys version in Makefile isn't equivalent to version of the nix package (allegedly ${finalAttrs.version}), failing."
@@ -150,16 +151,6 @@ in stdenv.mkDerivation (finalAttrs: {
   doCheck = true;
   nativeCheckInputs = [ verilog ];
 
-  # Internally, yosys knows to use the specified hardcoded ABCEXTERNAL binary.
-  # But other tools (like mcy or symbiyosys) can't know how yosys was built, so
-  # they just assume that 'yosys-abc' is available -- but it's not installed
-  # when using ABCEXTERNAL
-  #
-  # add a symlink to fake things so that both variants work the same way. this
-  # is also needed at build time for the test suite.
-  postBuild   = "ln -sfv ${abc-verifier}/bin/abc ./yosys-abc";
-  postInstall = "ln -sfv ${abc-verifier}/bin/abc $out/bin/yosys-abc";
-
   setupHook = ./setup-hook.sh;
 
   passthru = {

pkgs/development/compilers/yosys/fix-clang-build.patch

@@ -1,14 +1,3 @@
---- a/Makefile
-+++ b/Makefile
-@@ -215,7 +215,7 @@ ABC_ARCHFLAGS += "-DABC_NO_RLIMIT"
- endif
- 
- ifeq ($(CONFIG),clang)
--CXX = clang
-+CXX = clang++
- LD = clang++
- CXXFLAGS += -std=$(CXXSTD) -Os
- ABCMKARGS += ARCHFLAGS="-DABC_USE_STDINT_H -Wno-c++11-narrowing $(ABC_ARCHFLAGS)"
 --- a/tests/cxxrtl/run-test.sh
 +++ b/tests/cxxrtl/run-test.sh
 @@ -5,7 +5,7 @@ set -ex