Need option to use system gcc and binutils on Windows/msys2
Trying to build GHC 7.8.2 from sources on Windows 7, from msys2 shell, required binaries such as gcc, ld, ar are forced to those in inplace directories (windows-extra), even system/env provide such tools (e.g. using pacman package manager in msys2): https://ghc.haskell.org/trac/ghc/browser/ghc/configure.ac\#L274 .
It leads to issues as tools in inplace are quite old.
Particularly it can be critical about linking: GHC will be working with old ld, but you can have built/linked libraries using the more recent ld. Then, what's built using system tool can't be used throught GHC (ld version conflict).