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/networking/browsers/opera/default.nix

@@ -6,7 +6,7 @@
 , kdeSupport ? false, qt4, kdelibs
 }:
 
-assert stdenv.isLinux && stdenv.gcc.gcc != null && stdenv.gcc.libc != null;
+assert stdenv.isLinux && stdenv.cc.gcc != null && stdenv.cc.libc != null;
 
 let
   mirror = http://get.geo.opera.com/pub/opera;
@@ -37,7 +37,7 @@ stdenv.mkDerivation rec {
     '';
 
   buildInputs =
-    [ stdenv.gcc.gcc stdenv.gcc.libc zlib libX11 libXt libXext libSM libICE
+    [ stdenv.cc.gcc stdenv.cc.libc zlib libX11 libXt libXext libSM libICE
       libXft freetype fontconfig libXrender libuuid expat
       gstreamer libxml2 gst_plugins_base
     ]
@@ -57,7 +57,7 @@ stdenv.mkDerivation rec {
       elif [ $type == "EXEC" ]; then
         echo "patching $f executable <<"
         patchelf \
-            --set-interpreter "$(cat $NIX_GCC/nix-support/dynamic-linker)" \
+            --set-interpreter "$(cat $NIX_CC/nix-support/dynamic-linker)" \
             --set-rpath "${libPath}" \
             "$f"
       elif [ $type == "DYN" ]; then