New module sigaction, for mingw. * modules/sigaction: New module... * modules/sigaction-tests: ...and its test. * m4/sigaction.m4: New file. * lib/sigaction.c: Likewise. * tests/test-sigaction.c: Likewise. * m4/signal_h.m4 (gl_SIGNAL_H_DEFAULTS): Add sigaction variables. * modules/signal (Makefile.am): Likewise. * lib/signal.in.h (!@HAVE_SIGACTION@): Define replacements when needed. * doc/posix-headers/signal.texi (signal.h): Mention provided types. * doc/posix-functions/siginterrupt.texi (siginterrupt): Mention that sigaction is preferable. * doc/posix-functions/sigaction.texi (sigaction): Mention new module. * MODULES.html.sh (Support for systems lacking POSIX:2001): Add sigaction. Signed-off-by: Eric Blake <ebb9@byu.net>

@node signal.h
@section @file{signal.h}

POSIX specification: @url{http://www.opengroup.org/susv3xbd/signal.h.html}

Gnulib module: signal

Portability problems fixed by Gnulib:
@itemize
@item
@code{sigset_t} is only declared in <sys/types.h> on some platforms:
mingw.

@item
@code{struct sigaction} and @code{siginfo_t} are missing on some
platforms:
mingw.
@end itemize

Portability problems not fixed by Gnulib:
@itemize
@item
@code{struct sigaction} lacks the @code{sa_sigaction} member on some
platforms; this can also be detected by whether @code{SA_SIGINFO} is defined:
Interix 3.5.
@end itemize