free()d memory arenas on glibc-based systems.  Patch by Charles-François
Natali.

The problem is not specific to Mac OS X.

called. The test checks that SIG_UNBLOCK calls immediatly the signal handler of
the pending SIGUSR1. Improve also the tests using an exception (division by
zero) instead of a flag (a function attribute).

Disable faulthandler timeout thread on Mac OS X: it interacts with
pthread_sigmask() tests.

Patch by Victor Stinner.

to get around a mmap bug with sparse files. Patch written by Steffen Daode
Nurpmeso.

to get around a mmap bug with sparse files. Patch written by Steffen Daode
Nurpmeso.