Change occurrences of gcc to the more general cc

This is done for the sake of Yosemite, which does not have gcc, and yet
this change is also compatible with Linux.

pkgs/applications/editors/lighttable/default.nix

@@ -5,7 +5,7 @@
 
 let
   libPath = stdenv.lib.makeLibraryPath [
-      stdenv.gcc.gcc zlib glib dbus gtk atk pango freetype libgnome_keyring3 nss
+      stdenv.cc.gcc zlib glib dbus gtk atk pango freetype libgnome_keyring3 nss
       fontconfig gdk_pixbuf cairo cups expat libgpgerror alsaLib nspr gnome3.gconf
       xlibs.libXrender xlibs.libX11 xlibs.libXext xlibs.libXdamage xlibs.libXtst
       xlibs.libXcomposite xlibs.libXi xlibs.libXfixes
@@ -40,8 +40,8 @@ stdenv.mkDerivation rec {
     mv LightTable $out/
 
     patchelf \
-      --interpreter "$(cat $NIX_GCC/nix-support/dynamic-linker)" \
-      --set-rpath ${libPath}:${stdenv.gcc.gcc}/lib${stdenv.lib.optionalString stdenv.is64bit "64"} \
+      --interpreter "$(cat $NIX_CC/nix-support/dynamic-linker)" \
+      --set-rpath ${libPath}:${stdenv.cc.gcc}/lib${stdenv.lib.optionalString stdenv.is64bit "64"} \
       $out/LightTable/ltbin
 
     ln -s ${udev}/lib/libudev.so.1 $out/LightTable/libudev.so.0