s390.c (override_options): Don't emit an error when -mstack-size is used without providing -mstack-guard.

2007-03-07  Andreas Krebbel  <krebbel1@de.ibm.com>

	* config/s390/s390.c (override_options): Don't emit an error when
	-mstack-size is used without providing -mstack-guard.
	(s390_emit_prologue): Choose stack_guard value automatically if not
	provided via command line.
	* doc/invoke.texi: Adjust description of -mstack-guard and -mstack-size.

From-SVN: r122655