acinclude.m4 (LIBGFOR_CHECK_UNLINK_OPEN_FILE): Add check to see if target can unlink...

acinclude.m4 (LIBGFOR_CHECK_UNLINK_OPEN_FILE): Add check to see if target can unlink open files.

	* acinclude.m4 (LIBGFOR_CHECK_UNLINK_OPEN_FILE): Add check to see
	if target can unlink open files.
	* configure.ac: Use this new test.
	* config.h.in: Regenerate.
	* configure: Regenerate.
	* Makefile.in: Regenerate.
	* aclocal.ac: Regenerate.
	* io/io.h: Add prototype for unpack_filename.
	* io/close.c (st_close): Delete file after closing unit if
	HAVE_UNLINK_OPEN_FILE is not defined.
	* io/unix.c (unpack_filename): Unlink scratch file after opening
	it only if HAVE_UNLINK_OPEN_FILE is defined.

From-SVN: r103566