Use raise module consistently. * modules/fatal-signal (Depends-on): Add raise. * modules/sigprocmask (Depends-on): Likewise. * lib/fatal-signal.c (fatal_signal_handler): Rely on raise. * lib/sigprocmask.c (sigprocmask): Likewise. * m4/fatal-signal.m4 (gl_FATAL_SIGNAL): Likewise. * m4/signalblocking.m4 (gl_PREREQ_SIGPROCMASK): Likewise. Signed-off-by: Eric Blake <ebb9@byu.net>