Set close-on-exec flag when opening files.

2013-11-10  Janne Blomqvist  <jb@gcc.gnu.org>

	* configure.ac: Check presence of mkostemp.
	* io/unix.c (set_close_on_exec): New function.
	(tempfile_open): Use mkostemp and O_CLOEXEC if available, fallback
	to calling set_close_on_exec.
	(regular_file): Add O_CLOEXEC to flags if defined.
	(open_external): Call set_close_on_exec if O_CLOEXEC is not
	defined.
	* config.h.in: Regenerated.
	* configure: Regenerated.
	* Makefile.in: Regenerated.
	* aclocal.m4: Regenerated.

From-SVN: r204654