Check for the sched.h header and include it on gthread/gthread-posix.c if

Check for the sched.h header and include it on gthread/gthread-posix.c if

2000-11-15  Sebastian Wilhelmi  <wilhelmi@ira.uka.de>

	* configure.in: Check for the sched.h header and include it on
	gthread/gthread-posix.c if available.

	* gthread-posix.c: Include <sched.h> if available.

	* configure.in: Add -D_POSIX4_DRAFT_SOURCE to
	GTHREAD_COMPILE_IMPL_DEFINES. Also add -D_POSIX4A_DRAFT10_SOURCE
	to G_THREAD_CFLAGS. Really deploy GTHREAD_COMPILE_IMPL_DEFINES,
	when searching for thread libs. Look for sched_* functions in
	-lrte as well. All of that is necessary on DG/UX.

	* configure.in: Use AC_TRY_COMPILE instead of AC_EGREP_HEADERS in
	various places to make it work more reliable, to make it accept
	macros instead of functions etc.

	* configure.in: Replace some NULL's for checks with 0 to make it
	work without stdio.h everywhere.

	* configure.in, gutils.c: changed the test for getpwuid_r to first
	test for a posix version and then for a non-posix version. No code
	change in gutils.c. Again this change deals better with getpwuid_r
	being a macro and not a function. Most of the above with kind help
	from Tethys <tet@isengard.europe.dg.com>. This fixes Bug #13403.