cc-wrapper: Pull variable mangler into utils.sh

In preparation for splitting out bintools-wrapper

pkgs/build-support/cc-wrapper/cc-wrapper.sh

@@ -15,12 +15,12 @@ if [[ -n "@coreutils_bin@" && -n "@gnugrep_bin@" ]]; then
     PATH="@coreutils_bin@/bin:@gnugrep_bin@/bin"
 fi
 
+source @out@/nix-support/utils.sh
+
 if [ -z "${NIX_CC_WRAPPER_@infixSalt@_FLAGS_SET:-}" ]; then
     source @out@/nix-support/add-flags.sh
 fi
 
-source @out@/nix-support/utils.sh
-
 
 # Parse command line options and set several variables.
 # For instance, figure out if linker flags should be passed.