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.