GHC on Windows has hardcoded libtool path.

The GHC Windows bindists are shipping with a hardcoded libtool path.

 ,("libtool command","C:/msys64/usr/bin/libtool")

That's also not even the right libtool to use. The one that should be used is the mingw-w64 one. If libtool is now required as part of the compiler it should be included in the packaging.

This means http://repo.msys2.org/mingw/x86_64/mingw-w64-x86_64-libtool-2.4.6-15-any.pkg.tar.xz needs to be added to packages and it needs to be patched for long paths.

The remaining settings for clang, llc and opt are bogus too, but happen to work out because the machine configuring the Windows builds don't have clang, llc and opt installed.