Merge pull request #315717 from wegank/gtk-sharp-darwin

gtk-sharp-2_0: fix build on darwin

pkgs/development/libraries/gtk-sharp/2.0.nix

@@ -54,6 +54,10 @@ stdenv.mkDerivation rec {
     ./bootstrap-${lib.versions.majorMinor version}
   '';
 
+  env.NIX_CFLAGS_COMPILE = toString (lib.optionals stdenv.cc.isClang [
+    "-Wno-error=int-conversion"
+  ]);
+
   dontStrip = true;
 
   inherit monoDLLFixer;