Jobserver and Win32

[Jan Mikkelsen]

I've recently changed my makefiles to use VPATH and submakes instead of
using explict path prefixes for object directories.  This is great, my
makefiles are simpler, and the rules are cleaner.

However, on Win32 I have lost parallel builds.   Unix is fine.  I assume
this is because the jobserver code only runs on Unix, and without the
jobserver code, submakes get forced to -j1.

Is anyone working on Jobserver code for Win32?

Thanks,

Jan Mikkelsen