Re: Enabling the jobserver

> If you provide a limit you'll see different behavior, e.g.:
>
>   make -j5

I see, thank you. It might not hurt to mention this in the manual,
obvious though it may seem.

Having passed that hurdle, I see that GCC does not handle the
named-semaphore jobserver in native GNU Make on Windows. (I had to
read GCC's source to see it, since the error in that case simply says
"'--jobserver-auth=' is not present in MAKEFLAGS". This subproblem
appears to be unintentional and I have reported it on the GCC
bugtracker.) None of that is a Make problem, of course.