Head does not build on Windows with the default make config.
Cloning head and just running:
./boot ./configure --enable-tarballs-autodownload make
Fails since at least two weeks and still does as of a4ee2897
The main issue is the directory library fails to build.
Creating a build.mk file and setting the Flavour to quick GHC does build as expected.
What triggers the failure seems to be the windows.h file created by the directory library which in some way includes itself in a loop until the preprocessor/c-compiler gives up.
Renaming the file locally seems to be a viable workaround.
I used https://github.com/Mistuke/GhcDevelChoco to set up a build environment and it happens on both my machines so doesn't seem to be a fluke.