Parallel build fails with 3.82

[Burton, Ross]

Hi,

I'm doing builds of WebKit with make -j8 because it reduces the build
time from hours to 20 minutes on my build machine, but with GNU Make
3.82 there are occasional build failures due to what appears to be a
problem in 3.82 (not 3.81).

The WebKit bug is https://bugs.webkit.org/show_bug.cgi?id=79498, and
people discovered that the Make bug
http://savannah.gnu.org/bugs/?30653 not only describes the problem,
but has two independent patches for it.

This bug and the patches are now two years old - it would be good if a
patch could be integrated or at least reviewed and rejected with a
reason.

Cheers,
Ross