See attached 6923488-webrev-cr0.tgz for the proposed fix.
Tweak get_msc_ver to be more clear about Cygwin support. Also be
more explicit about using the "link" command that is co-located
with the "cl" command. Also, while I'm here, add "tree" option
support to build.bat and build.make so those behave more like
the Solaris version.