Use mingw-w64 for 32bit Windows builds as well.

Mingw(32) is rather poorly maintaned and has quite a lot of bugs. And
because our Windows cross builds were also poorly maintained and most of
the cross-tests were broken as well, I'm just taking this step and try
to switch to mingw-w64 for everything "cross Windows".

Signed-off-by: aszlig <aszlig@redmoonstudios.org>

pkgs/development/libraries/SDL/default.nix

@@ -47,7 +47,7 @@ stdenv.mkDerivation rec {
 
   crossAttrs = {
     configureFlags = configureFlagsFun {
-      alsaSupport = stdenv.cross.config != "x86_64-w64-mingw32";
+      alsaSupport = stdenv.cross.libc != "msvcrt";
       alsaLib = alsaLib.crossDrv;
     } + "--disable-directx";
   };