wxHaskell: patch wxc to fix build error

pkgs/development/libraries/haskell/wxHaskell/fix-bogus-pointer-assignment.patch

@@ -0,0 +1,13 @@
+diff -ubr wxc-0.90.0.4-orig/src/cpp/eljpen.cpp wxc-0.90.0.4/src/cpp/eljpen.cpp
+--- wxc-0.90.0.4-orig/src/cpp/eljpen.cpp	2012-07-03 12:12:17.000000000 +0200
++++ wxc-0.90.0.4/src/cpp/eljpen.cpp	2013-01-07 12:09:50.296417007 +0100
+@@ -156,7 +156,7 @@
+ EWXWEXPORT(void,wxPen_GetStipple)(void* self,wxBitmap* _ref)
+ {
+ #if defined(__WXGTK__)
+-    *_ref = NULL;
++    _ref = NULL;
+ #else
+     *_ref = *(((wxPen*)self)->GetStipple());
+ #endif
+Only in wxc-0.90.0.4/src/cpp: eljpen.cpp.orig

pkgs/development/libraries/haskell/wxHaskell/wxc.nix

@@ -10,7 +10,7 @@ cabal.mkDerivation (self: {
   postInstall = ''
     cp -v dist/build/libwxc.so.${self.version} $out/lib/libwxc.so
   '';
-
+  patches = [ ./fix-bogus-pointer-assignment.patch ];
   meta = {
     homepage = "http://haskell.org/haskellwiki/WxHaskell";
     description = "wxHaskell C++ wrapper";