[master b3cf281] Unbreak the MinGW build

[Eli Zaretskii]

Paul,

I needed this commit to prevent temacs from crashing during dumping.
Don't ask me how including errno.h (both the one from Gnulib and the
MinGW one) could cause this, especially as the preprocessed __fpending
doesn't seem to change a bit as result of that, and it doesn't seem to
even be called during dumping.  The facts are stubborn: if I leave
that inclusion in place, I get a crash, removing it fixes the crash.

Any ideas?