Create Makefile.windows

[PP-AR-T]

This small change allowed me to run "make" using windows, and to avoid errors like:

"rm -rf .gitmodules && rm -rf .git/modules/* && rm -rf lib && touch .gitmodules && git add . && git commit -m "modules" 'rm' is not recognized as an internal or external command, operable program or batch file."

Adding it in case its useful for other people running this in windows.