ghdl: fix environment for llvm and gcc backends

gcc backend needs as on path, llvm requires the full gcc compiler suite,
so just add stdenv.cc to both.
Both also need to link against zlib, so add it to the library paths
The problems arose in `nix shell nixpkgs#ghdl-llvm` and adding it to a
system environment, not `nix-shell -p ghdl-llvm` because that added gcc
and other things to the path. __structuredAttrs may also have affected
this

Fixes: #113401

pkgs/by-name/gh/ghdl/package.nix

@@ -37,29 +37,22 @@ stdenv.mkDerivation (finalAttrs: {
   nativeBuildInputs = [
     gnat
   ]
+  ++ lib.optionals (backend == "llvm" || backend == "gcc") [
+    makeWrapper
+  ]
   ++ lib.optionals (backend == "gcc") [
     texinfo
-    makeWrapper
   ];
 
   buildInputs = [
     zlib
   ]
-  ++ lib.optionals (backend == "llvm") [
-    llvm
-  ]
   ++ lib.optionals (backend == "gcc") [
     gmp
     mpfr
     libmpc
   ];
 
-  propagatedBuildInputs = [
-  ]
-  ++ lib.optionals (backend == "llvm" || backend == "gcc") [
-    zlib
-  ];
-
   preConfigure = ''
     # If llvm 7.0 works, 7.x releases should work too.
     sed -i 's/check_version  7.0/check_version  7/g' configure
@@ -99,20 +92,18 @@ stdenv.mkDerivation (finalAttrs: {
       --with-gmp-lib=${gmp.out}/lib \
       --with-mpfr-include=${mpfr.dev}/include \
       --with-mpfr-lib=${mpfr.out}/lib \
-      --with-mpc=${libmpc}
+      --with-mpc=${libmpc} \
+      --enable-default-pie=${if stdenv.targetPlatform.hasSharedLibraries then "yes" else "no"}
     make -j $NIX_BUILD_CORES
     make install
     cd ../
     make -j $NIX_BUILD_CORES ghdllib
   '';
 
-  postFixup = lib.optionalString (backend == "gcc") ''
+  postFixup = lib.optionalString (backend == "llvm" || backend == "gcc") ''
     wrapProgram $out/bin/ghdl \
-      --set LIBRARY_PATH ${
-        lib.makeLibraryPath [
-          stdenv.cc.libc
-        ]
-      }
+      --set LIBRARY_PATH ${lib.makeLibraryPath [ zlib ]} \
+      --prefix PATH : ${lib.makeBinPath [ stdenv.cc ]}
   '';
 
   hardeningDisable = [