compcert: clean up expression

- Require Coq 8.6.1+
  - Split substituteInPlace call into patchPhase
  - Constrain platforms correctly to x86_64 Linux/Darwin, which was all
it supported anyway (there was no way to properly configure i686 builds,
nor cross builds. In the future there might be)
  - Minor stylistic cleanups
  - Add new 'man' and 'doc' outputs (the previous attempt to move the
build artifact outputs into $lib no longer worked correctly and they
were installed into 'out' instead, this fixes it completely).
  - Clean up weird binary artifacts left in $out (that were already
in $lib)
  - Wrap ccomp to undefine _FORTIFY_SOURCE; otherwise it causes
annoying warnings on every invocation

Signed-off-by: Austin Seipp <aseipp@pobox.com>

pkgs/development/compilers/compcert/default.nix

@@ -1,10 +1,15 @@
-{ stdenv, lib, fetchurl, fetchpatch
+{ stdenv, lib, fetchurl, fetchpatch, makeWrapper
 , coq, ocamlPackages, coq2html
 , tools ? stdenv.cc
 }:
 
 assert lib.versionAtLeast ocamlPackages.ocaml.version "4.02";
+assert lib.versionAtLeast coq.coq-version "8.6.1";
 
+let
+  ocaml-pkgs      = with ocamlPackages; [ ocaml findlib menhir ];
+  ccomp-platform = if stdenv.isDarwin then "x86_64-macosx" else "x86_64-linux";
+in
 stdenv.mkDerivation rec {
   name    = "compcert-${version}";
   version = "3.4";
@@ -14,34 +19,53 @@ stdenv.mkDerivation rec {
     sha256 = "12gchwvkzhd2bhrnwzfb4a06wc4hgv98z987k06vj7ga31ii763h";
   };
 
-  buildInputs = [ coq coq2html ]
-  ++ (with ocamlPackages; [ ocaml findlib menhir ]);
-
+  nativeBuildInputs = [ makeWrapper ];
+  buildInputs = ocaml-pkgs ++ [ coq coq2html ];
   enableParallelBuilding = true;
 
+  patchPhase = ''
+    substituteInPlace ./configure \
+      --replace '{toolprefix}gcc' '{toolprefix}cc'
+  '';
+
   configurePhase = ''
-    substituteInPlace ./configure --replace '{toolprefix}gcc' '{toolprefix}cc'
-    ./configure -clightgen -prefix $out -toolprefix ${tools}/bin/ '' +
-    (if stdenv.isDarwin then "x86_64-macosx" else "x86_64-linux");
+    ./configure -clightgen \
+      -prefix $out \
+      -toolprefix ${tools}/bin/ \
+      ${ccomp-platform}
+  '';
 
   installTargets = "documentation install";
-
   postInstall = ''
-    mkdir -p $lib/share/doc/compcert
-    mv doc/html $lib/share/doc/compcert/
+    # move man into place
+    mkdir -p $man/share
+    mv $out/share/man/ $man/share/
+
+    # move docs into place
+    mkdir -p $doc/share/doc/compcert
+    mv doc/html $doc/share/doc/compcert/
+
+    # install compcert lib files; remove copy from $out, too
     mkdir -p $lib/lib/coq/${coq.coq-version}/user-contrib/compcert/
     mv backend cfrontend common cparser driver flocq x86 x86_64 lib \
       $lib/lib/coq/${coq.coq-version}/user-contrib/compcert/
+    rm -rf $out/lib/compcert/coq
+
+    # wrap ccomp to undefine _FORTIFY_SOURCE; ccomp invokes cc1 which sets
+    # _FORTIFY_SOURCE=2 by default, but undefines __GNUC__ (as it should),
+    # which causes a warning in libc. this suppresses it.
+    for x in ccomp clightgen; do
+      wrapProgram $out/bin/$x --add-flags "-U_FORTIFY_SOURCE"
+    done
   '';
 
-  outputs = [ "out" "lib" ];
+  outputs = [ "out" "lib" "doc" "man" ];
 
   meta = with stdenv.lib; {
     description = "Formally verified C compiler";
     homepage    = "http://compcert.inria.fr";
     license     = licenses.inria-compcert;
-    platforms   = platforms.linux ++
-                  platforms.darwin;
+    platforms   = [ "x86_64-linux" "x86_64-darwin" ];
     maintainers = with maintainers; [ thoughtpolice jwiegley vbgl ];
   };
 }