Systools makes some pretty hard assumptions about where GHC is on Windows.
One of these is that ghc be in a folder named bin and that ../lib exists.
This pattern doesn't hold for symlinks as a link C:\ghc-bin\
pointing to C:\ghc\ghc-7.10.3\bin will break this assumption.
This patch resolves symlinks by finding where they point to and uses that location
as the base for GHC.
This uses an API that's been introduced in Vista. For older systems it falls back to
the current behavior of not resolving symlinks.