The new GHC version contains a patch [1] that passes linker and compiler flags
to GCC via response files rather than directly on the command-line. This is
supposed to be beneficial on Windows and other platforms that have trouble
dealing with long argument lists. On NixOS, however, this feature breaks the
flag handling provided by gcc-wrapper [2] and therefore causes the entire GHC
build to fail.
This issue has been reported upstream at [3]. It's not clear yet how to remedy
this problem, but until we've figured that out we just don't pass compiler flags
in response files on NixOS to fix https://github.com/NixOS/nixpkgs/issues/10752.
[1] 296bc70b5f
[2] https://github.com/NixOS/nixpkgs/issues/11762
[3] https://ghc.haskell.org/trac/ghc/ticket/11147
a421e7bd4a