ccacheWrapper: make usable with clang

Override original `wrapCCWith` call to preserve essential arguments

pkgs/top-level/all-packages.nix

···
   #     };
   # You can use a different directory, but whichever directory you choose
   # should be owned by user root, group nixbld with permissions 0770.
-  ccacheWrapper = makeOverridable ({ extraConfig ? "", unwrappedCC ? stdenv.cc.cc }:
-     wrapCC (ccache.links {inherit unwrappedCC extraConfig;})) {};
+  ccacheWrapper = makeOverridable ({ extraConfig ? "", cc ? stdenv.cc }:
+    cc.override { cc = ccache.links {
+      inherit extraConfig;
+      unwrappedCC = cc.cc;
+    }; }) {};
   ccacheStdenv = lowPrio (overrideCC stdenv buildPackages.ccacheWrapper);
 
   cccc = callPackage ../development/tools/analysis/cccc { };