[OS] Another data point for OS / ASL under Msys / cl

[Lou Hafer]

Folks,

	I think I'm making pretty good progress on this --- I've figured out how
to pass the BuildTools settings of CFLAGS into the nmake build of ASL, so that
should deal with the libCMT / lib CMTd problem.  I'm working on a macro to
properly detect the right spec for network libraries (there are four variations
I've run across so far).  Will spend a bit more time today.  Once I can
configure and build OS again I'll be able to see if it all hangs together.

							Lou