polyml: Fix polyc linking script

polyc linking script hardcodes the linker to be the value of `$CXX` at
compile time. This is bad for environments without `g++` in path. Fix
this by patching the correct path into the script.

Co-Authored-By: Ricardo Correia <someplaceguy@wizy.org>
Co-Authored-By: Ivan Trubach <mr.trubach@icloud.com>

pkgs/by-name/po/polyml/package.nix

@@ -1,6 +1,7 @@
 {
   lib,
   stdenv,
+  pkgsHostTarget,
   fetchFromGitHub,
   autoreconfHook,
   gmp,
@@ -35,6 +36,7 @@ stdenv.mkDerivation (finalAttrs: {
   buildInputs = [
     libffi
     gmp
+    pkgsHostTarget.stdenv.cc
   ];
 
   nativeBuildInputs = [ autoreconfHook ];
@@ -45,6 +47,11 @@ stdenv.mkDerivation (finalAttrs: {
     "--with-gmp"
   ];
 
+  preInstall = ''
+    substituteInPlace polyc \
+      --replace-fail "LINK=\"$CXX\"" "LINK=\"${lib.getExe' pkgsHostTarget.stdenv.cc "c++"}\""
+  '';
+
   doCheck = true;
 
   meta = {