perl merge fixup

pkgs/development/interpreters/perl/default.nix

@@ -17,7 +17,8 @@ assert enableThreading -> (stdenv ? glibc);
 let
 
   libc = if stdenv.cc.libc or null != null then stdenv.cc.libc else "/usr";
-
+  libcInc = libc.dev or libc;
+  libcLib = libc.out or libc;
   common = { version, sha256 }: stdenv.mkDerivation rec {
     name = "perl-${version}";
 
@@ -26,7 +27,9 @@ let
       inherit sha256;
     };
 
-    outputs = [ "out" "man" ];
+    # TODO: Add a "dev" output containing the header files.
+    outputs = [ "out" "man" "docdev" ];
+    setOutputFlags = false;
 
     patches =
       [ # Do not look in /usr etc. for dependencies.
@@ -35,17 +38,11 @@ let
       ++ optional stdenv.isSunOS ./ld-shared.patch
       ++ optional stdenv.isDarwin [ ./cpp-precomp.patch ];
 
-    # There's an annoying bug on sandboxed Darwin in Perl's Cwd.pm where it looks for pwd
-    # in /bin/pwd and /usr/bin/pwd and then falls back on just "pwd" if it can't get them
-    # while at the same time erasing the PATH environment variable so it unconditionally
-    # fails. The code in question is guarded by a check for Mac OS, but the patch below
-    # doesn't have any runtime effect on other platforms.
-    postPatch = optional stdenv.isDarwin ''
+    postPatch = ''
       pwd="$(type -P pwd)"
       substituteInPlace dist/PathTools/Cwd.pm \
         --replace "/bin/pwd" "$pwd"
     '';
-
     sandboxProfile = sandbox.allow "ipc-sysv-sem";
 
     # Build a thread-safe Perl with a dynamic libperls.o.  We need the
@@ -59,8 +56,8 @@ let
         "-Uinstallusrbinperl"
         "-Dinstallstyle=lib/perl5"
         "-Duseshrplib"
-        "-Dlocincpth=${libc}/include"
-        "-Dloclibpth=${libc}/lib"
+        "-Dlocincpth=${libcInc}/include"
+        "-Dloclibpth=${libcLib}/lib"
       ]
       ++ optional stdenv.isSunOS "-Dcc=gcc"
       ++ optional enableThreading "-Dusethreads";
@@ -74,10 +71,8 @@ let
     preConfigure =
       ''
         configureFlags="$configureFlags -Dprefix=$out -Dman1dir=$out/share/man/man1 -Dman3dir=$out/share/man/man3"
-
-        ${optionalString stdenv.isArm ''
-          configureFlagsArray=(-Dldflags="-lm -lrt")
-        ''}
+    '' + optionalString stdenv.isArm ''
+      configureFlagsArray=(-Dldflags="-lm -lrt")
       '' + optionalString stdenv.isDarwin ''
         substituteInPlace hints/darwin.sh --replace "env MACOSX_DEPLOYMENT_TARGET=10.3" ""
       '' + optionalString (!enableThreading) ''
@@ -91,18 +86,26 @@ let
         substituteInPlace dist/PathTools/Cwd.pm --replace "'/bin/pwd'" "'$(type -tP pwd)'"
       '';
 
-    # Inspired by nuke-references, which I can't depend on because it uses perl. Perhaps it should just use sed :)
-    postInstall = ''
-      self=$(echo $out | sed -n "s|^$NIX_STORE/\\([a-z0-9]\{32\}\\)-.*|\1|p")
-
-      sed -i "/$self/b; s|$NIX_STORE/[a-z0-9]\{32\}-|$NIX_STORE/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-|g" "$out"/lib/perl5/*/*/Config.pm
-      sed -i "/$self/b; s|$NIX_STORE/[a-z0-9]\{32\}-|$NIX_STORE/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-|g" "$out"/lib/perl5/*/*/Config_heavy.pl
-    '';
-
     setupHook = ./setup-hook.sh;
 
     passthru.libPrefix = "lib/perl5/site_perl";
 
+  # TODO: it seems like absolute paths to some coreutils is required.
+  postInstall =
+    ''
+      # Remove dependency between "out" and "man" outputs.
+      rm "$out"/lib/perl5/*/*/.packlist
+
+      # Remove dependencies on glibc and gcc
+      sed "/ *libpth =>/c    libpth => ' '," \
+        -i "$out"/lib/perl5/*/*/Config.pm
+      # TODO: removing those paths would be cleaner than overwriting with nonsense.
+      substituteInPlace "$out"/lib/perl5/*/*/Config_heavy.pl \
+        --replace "${libcInc}" /no-such-path \
+        --replace "${stdenv.cc.cc or "/no-such-path"}" /no-such-path \
+        --replace "$man" /no-such-path
+    ''; # */
+
     meta = {
       homepage = https://www.perl.org/;
       description = "The standard implementation of the Perl 5 programmming language";