?RCS: $Id: i_ucontext.U 167 2013-05-08 17:58:00Z rmanfredi $
?RCS:
?RCS: Copyright (c) 2012 Raphael Manfredi
?RCS: 
?RCS: You may redistribute only under the terms of the Artistic License,
?RCS: as specified in the README file that comes with the distribution.
?RCS: You may reuse parts of this distribution only within the terms of
?RCS: that same Artistic License; a copy of which may be found at the root
?RCS: of the source tree for dist 4.0.
?RCS:
?MAKE:i_ucontext i_sys_ucontext: Inhdr cat echo n c rm \
	+cc +ccflags +ldflags
?MAKE:	-pick add $@ %<
?S:i_ucontext:
?S:	This variable conditionally defines the I_UCONTEXT symbol, and indicates
?S:	whether a C program may include <ucontext.h> to get ucontext_t.
?S:.
?S:i_sys_ucontext:
?S:	This variable conditionally defines the I_SYS_UCONTEXT symbol, and
?S:	indicates whether a C program may include <sys/ucontext.h> to get
?S:	ucontext_t.
?S:.
?C:I_UCONTEXT:
?C:	This symbol, if defined, indicates to the C program that it should
?C:	include <ucontext.h> to get at the user thread context.  A portable
?C:	program must also check I_SYS_UCONTEXT for <sys/ucontex.h> inclusion,
?C:	especially on OSX.
?C:.
?C:I_SYS_UCONTEXT:
?C:	This symbol, if defined, indicates to the C program that it should
?C:	include <sys/ucontext.h> to get at the user thread context.  A portable
?C:	program must also check I_UCONTEXT for <ucontex.h> inclusion.
?C:.
?H:#$i_ucontext I_UCONTEXT		/**/
?H:#$i_sys_ucontext I_SYS_UCONTEXT		/**/
?H:.
?T:working
: see if this is a ucontext.h system
set ucontext.h i_ucontext
eval $inhdr

: see if this is a sys/ucontext.h system
set sys/ucontext.h i_sys_ucontext
eval $inhdr

: when both ucontext.h and sys/ucontext.h are available, check which one works
case "$i_ucontext$i_sys_ucontext" in
"$define$define")
	echo " "
	$cat >try.c <<'EOC'
#ifdef I_UCONTEXT
#include <ucontext.h>
#endif
#ifdef I_SYS_UCONTEXT
#include <sys/ucontext.h>
#endif

int main(void)
{
	static ucontext_t u;
	return (int) sizeof(u) & 0xff;
}
EOC
	$echo $n "Checking whether including <ucontext.h> alone works...$c" >&4
	working=
	if $cc $ccflags -DI_UCONTEXT -o try try.c $ldflags >/dev/null 2>&1; then
		working="$define"
	fi
	case "$working" in
	"$define")
		echo " yes." >&4
		i_sys_ucontext="$undef"
		;;
	*)
		echo "no." >&4
		echo " "
		$echo $n "Checking whether including <sys/ucontext.h> works...$c" >&4
		working=
		if $cc $ccflags -DI_SYS_UCONTEXT \
			-o try try.c $ldflags >/dev/null 2>&1
		then
			working="$define"
		fi
		case "$working" in
		"$define")
			echo " yes, ignoring <ucontext.h>." >&4
			i_ucontext="$undef"
			;;
		*) echo " no, we'll include both then." >&4;;
		esac
		;;
	esac
	;;
esac
$rm -f try.*