Track changes in platform.sh
Track changes in platform.sh

* windows-platform.sh
  * pick up some robustness fixes from platform.sh
  * add a few more sanity checks for Windows (easier to catch
    these before the long build starts and it then hits them)

erantapaa/haskell-platform,gbaz/haskell-platform,ardumont/haskell-platform,ardumont/haskell-platform,erantapaa/haskell-platform,erantapaa/haskell-platform,gbaz/haskell-platform