raise: Support for MSVC.

raise: Support for MSVC.

* lib/signal.in.h (raise): New declaration.
* lib/raise.c (raise_nothrow, rpl_raise): New alternate implementation
for native Windows platforms.
* m4/raise.m4: New file.
* m4/signal_h.m4 (gl_SIGNAL_H_DEFAULTS): Initialize GNULIB_RAISE,
HAVE_RAISE, REPLACE_RAISE.
* modules/signal (Makefile.am): Substitute GNULIB_RAISE, HAVE_RAISE,
REPLACE_RAISE.
* modules/raise (Status, Notice): Remove fields.
(Files): Add m4/raise.m4.
(Depends-on): Add signal, msvc-inval.
(configure.ac): Use the common idioms.
(Maintainer): Add me.
* tests/test-signal-c++.cc: Check the signature of raise.
* doc/posix-functions/raise.texi: Mention the problem on MSVC.