Don't set the signal handler for SIGQUIT on Windows. Buildfarm shows that

Don't set the signal handler for SIGQUIT on Windows. Buildfarm shows that
reinstalling the default signal handler doesn't work as it is on Windows.
Presumably core dumps on SIGQUIT are not a problem on Windows, so rather
than figure out what header files or other changes are required to make it
work, just don't bother.