sigwait
=======

POSIX specification:
 http://www.opengroup.org/onlinepubs/9699919799/functions/sigwait.html

Gnulib module: extensions

Portability problems fixed by Gnulib:

  * This function has an incompatible declaration on some platforms: Solaris 11 2010-11 (when _POSIX_PTHREAD_SEMANTICS is not defined).

Portability problems not fixed by Gnulib:

  * This function is missing on some platforms: Minix 3.1.8, mingw, BeOS.

  * On Linux/glibc platforms before the advent of NPTL, signals could only be sent to one particular thread.  In POSIX, signals are sent to the entire process and executed by any thread of the process that happens to have the particular signal currently unblocked.