treewide: add targetPrefix to hardcoded references to CC=cc

pkgs/development/libraries/java/junixsocket/default.nix

@@ -23,7 +23,7 @@ stdenv.mkDerivation rec {
   ANT_ARGS =
     # Note that our OpenJDK on Darwin is currently 32-bit, so we have to build a 32-bit dylib.
     (if stdenv.is64bit then [ "-Dskip32=true" ] else [ "-Dskip64=true" ])
-    ++ [ "-Dgcc=cc" "-Dant.build.javac.source=1.6" ]
+    ++ [ "-Dgcc=${stdenv.cc.targetPrefix}cc" "-Dant.build.javac.source=1.6" ]
     ++ lib.optional stdenv.isDarwin "-DisMac=true";
 
   installPhase =