gcc-wrapper doesn't handle compiler/linker flags passed through response files.
One package which recently started using such files is GHC (I believe since 7.10.3). For this reason we currently need to patch it. However, the problem is with our tool chain wrapper and not with GHC itself. See discussion at https://lists.gnu.org/archive/html/guix-devel/2017-01/msg01981.html
