cc-wrapper: remove quoting of response file

Fixes build failures with clang:

    clang-7: error: unknown argument: '-fPIC                -target'
    clang-7: error: no such file or directory: '@<(printf %qn        -O2'
    clang-7: error: no such file or directory: 'x86_64-apple-darwin'

Introduced by 60c5cf9cea in #112449

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

@@ -200,10 +200,10 @@ PATH="$path_backup"
 # Old bash workaround, see above.
 
 if (( "${NIX_CC_USE_RESPONSE_FILE:-@use_response_file_by_default@}" >= 1 )); then
-    exec @prog@ "@<(printf "%q\n" \
+    exec @prog@ @<(printf "%q\n" \
        ${extraBefore+"${extraBefore[@]}"} \
        ${params+"${params[@]}"} \
-       ${extraAfter+"${extraAfter[@]}"})"
+       ${extraAfter+"${extraAfter[@]}"})
 else
     exec @prog@ \
        ${extraBefore+"${extraBefore[@]}"} \