cc-wrapper: Use stdenvNoCC to build

cc-wrapper may wrap a cc-compiler, but it doesn't need one to build
itself. (c.f. expand-response-params is a separate derivation.) This
helps avoid cycles on the cross stuff, in addition to removing a
useless dependency edge.

I could have been super careful with overrides in the stdenv to avoid
the mass rebuild, but I don't think it's worth it.

pkgs/stdenv/native/default.nix

@@ -117,6 +117,7 @@ in
       cc = null;
       fetchurl = null;
     };
+    stdenvNoCC = stdenv;
 
     cc = import ../../build-support/cc-wrapper {
       name = "cc-native";
@@ -126,7 +127,7 @@ in
         "i686-solaris" = "/usr/gnu";
         "x86_64-solaris" = "/opt/local/gcc47";
       }.${system} or "/usr";
-      inherit stdenv;
+      inherit stdenvNoCC;
     };
 
     fetchurl = import ../../build-support/fetchurl {