I see that anything involving ghci fails:

/c/code/HEAD/inplace/bin/ghc-stage2 --interactive

GHCi, version 8.1.20161209: http://www.haskell.org/ghc/  :? for help

ghc-stage2.exe: unable to load package `base-4.9.0.0'

ghc-stage2.exe: C:\code\HEAD\inplace\mingw\x86_64-w64-mingw32\lib\libmingwex.a: unknown symbol `_lock_file'

ghc-stage2.exe: Could not on-demand load symbol '__mingw_vfprintf'

ghc-stage2.exe: C:\code\HEAD\libraries\base\dist-install\build\HSbase-4.9.0.0.o: unknown symbol `__mingw_vfprintf'

It’s frustrating.  It used to work!

Simon