Fix fallout of recent cc-wrapper changes

Fixes tarball except for 56e21d05e8

pkgs/development/compilers/gcc/3.4/default.nix

@@ -37,7 +37,7 @@ stdenv.mkDerivation {
     }
   ";
 
-  passthru = { inherit langC langCC langF77; };
+  passthru = { inherit langC langCC langF77; isGNU = true; };
 
   meta = {
     homepage = "http://gcc.gnu.org/";

pkgs/development/compilers/gcc/4.3/default.nix

@@ -171,6 +171,8 @@ stdenv.mkDerivation ({
     rm -Rf ghdl-*
   '';
 
+  passthru.isGNU = true;
+
   meta = {
     homepage = "http://ghdl.free.fr/";
     license = stdenv.lib.licenses.gpl2Plus;

pkgs/development/compilers/gcc/4.4/default.nix

@@ -243,7 +243,7 @@ stdenv.mkDerivation ({
 
 
   passthru = { inherit langC langCC langAda langFortran langVhdl
-      enableMultilib version; };
+      enableMultilib version; isGNU = true; };
 
   # ghdl does not build fine with parallel building
   # http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46173

pkgs/development/compilers/gcc/4.5/default.nix

@@ -358,7 +358,7 @@ stdenv.mkDerivation ({
     else null;
 
   passthru = { inherit langC langCC langAda langFortran langVhdl
-      enableMultilib version; };
+      enableMultilib version; isGNU = true; };
 
   enableParallelBuilding = !langAda;
 

pkgs/development/compilers/gcc/4.6/default.nix

@@ -427,7 +427,7 @@ stdenv.mkDerivation ({
     else null;
 
   passthru = { inherit langC langCC langAda langFortran langVhdl
-      langGo version; };
+      langGo version; isGNU = true; };
 
   enableParallelBuilding = false;