i386.opt: New option mstack-protector-guard=.

i386.opt: New option mstack-protector-guard=.

	* config/i386/i386.opt: New option mstack-protector-guard=.
	* config/i386/i386-opts.h: Add enum stack_protector_guard.
	* config/i386/i386.h: Define TARGET_SSP_GLOBAL_GUARD and
	TARGET_SSP_TLS_GUARD.
	* config/i386/i386.c (ix86_option_override_internal): Set
	ix86_stack_protector_guard.
	* config/i386/i386.md (stack_protect_set): Enable for
	TARGET_SSP_TLS_GUARD only.
	(stack_protect_set_<mode>): Ditto.
	(stack_protect_test): Ditto.
	(stack_protect_test_<mode>): Ditto.
	* doc/invoke.texi (i386 Option): Document.

From-SVN: r197963