Adding test target to Make_cyg_ming.mak

[Michael Soyka]

Vim developers,

I am in the process of adding a "test" target to Make_cyg_ming.mak so that the test suite can be run from src. 

That makefile supports cygwin builds as well as mingw builds. 

My question is which makefile in testdir is used when testing the cygwin build?  I looks like it would be "Makefile" but I'm not sure.

Thanks,

-mike