cc-wrapper: don't expand $ in response files

This makes the response file handling more consistent with GCC.

For example, a reponse file may contain:

    "-Wl,$ORIGIN"

GCC will treat this as a double quoted string and not expand the
variable reference.  Previously, cc-wrapper would expand the variable
in the same was as if the string was provided on the command line.

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

@@ -34,7 +34,7 @@ expandResponseParams() {
             @*)
                 if [ -e "${p:1}" ]; then
                     args=$(<"${p:1}")
-                    eval 'for arg in '$args'; do params+=("$arg"); done'
+                    eval 'for arg in '${args//$/\\$}'; do params+=("$arg"); done'
                 else
                     params+=("$p")
                 fi