Basic AppVeyor build.
Set libffi flags for ctypes build.
Link libffi headers to /usr/local/include
hardcode libffi paths for now
add -verbose flag
opt commands.
s/exe//
.
findlib
Patch findlib to use Unix.system instead of Unix.create_process
Download libffi; download and patch findlib.
Disable explicit environment variables.
build setup.data again
Disable makefile debugging