This directory provides a signal implementation, which is appropriate
for operating systems where signals are managed at user-level.  It is
up to the run-time to catch the signals and forward them to the
implementation via, e.g., the pthread_kill_info_np call.

The files in this directory are accompanied by the generic implementations
found in sysdeps/generic/: killpg.c, raise.c, sigaddset.c, sigdelset.c,
sigemptyset.c, sigfillset.c, siginterrupt.c, sigismember.c, signal.c,
sigwait.c.

This implementation was once used for a native port running on L4, but is not
currently used in any libpthread port bundled in this release.