The WIN32 CreateProcess() function does not require an .exe or .com
suffix in order to spawn an executable. Now that we have Cosmo bash
we're no longer so dependent on the cmd.exe prompt.
It turned out that specifying all SRCS and INCS as dependencies on the
pattern rules for all headers, caused `make` memory usage to skyrocket
from 40mb ot 160mb. This change also reduces the build graph another 4%.
