stddef: fix NetBSD 5.0 NULL bug, rather than working around it * tests/test-locale.c: Revert previous patch related to NULL. * tests/test-stdio.c: Likewise. * tests/test-stdlib.c: Likewise. * tests/test-string.c: Likewise. * tests/test-unistd.c: Likewise. * modules/time-tests (Depends-on): Add verify. * modules/wchar-tests (Depends-on): Likewise. * tests/test-time.c: Test for NULL compliance. * tests/test-wchar.c: Likewise. * modules/locale (Depends-on): Add stddef. * modules/stdio (Depends-on): Likewise. * modules/stdlib (Depends-on): Likewise. * modules/string (Depends-on): Likewise. * modules/time (Depends-on): Likewise. * modules/unistd (Depends-on): Likewise. * modules/wchar (Depends-on): Likewise. * lib/locale.in.h (includes): Use <stddef.h> to fix NULL. * lib/stdlib.in.h (includes): Likewise. * lib/string.in.h (includes): Likewise. * lib/time.in.h (includes): Likewise. * lib/unistd.in.h (includes): Likewise. * m4/locale_h.m4 (gl_LOCALE_H): Replace locale.h if stddef.h was replaced. * m4/wchar.m4 (gl_WCHAR_H): Likewise. * m4/stddef_h.m4: New file. * modules/stddef: Likewise. * lib/stddef.in.h: Likewise. * modules/stddef-tests: Likewise. * tests/test-stddef.c: Likewise. * MODULES.html.sh (Basic types <stddef.h>): Mention new module. * doc/posix-headers/stddef.texi (stddef.h): Document the bug. * doc/posix-headers/locale.texi (locale.h): Likewise. * doc/posix-headers/stdio.texi (stdio.h): Likewise. * doc/posix-headers/stdlib.texi (stdlib.h): Likewise. * doc/posix-headers/string.texi (string.h): Likewise. * doc/posix-headers/time.texi (time.h): Likewise. * doc/posix-headers/unistd.texi (unistd.h): Likewise. * doc/posix-headers/wchar.texi (wchar.h): Likewise. Signed-off-by: Eric Blake <ebb9@byu.net>

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

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

Gnulib module: string

Portability problems fixed by Gnulib:
@itemize
@item
Some platforms provide a @code{NULL} macro that cannot be used in arbitrary
expressions:
NetBSD 5.0
@end itemize

Portability problems not fixed by Gnulib:
@itemize
@end itemize