PR target/23070

	* config/rs6000/rs6000.c (function_arg): For ABI_V4 calls to
	stdarg functions, set/clear the fp marker even when no variable
	args are passed.
	* config/rs6000/sysv4.opt (mprototype): Describe.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@103375 138bc75d-0d04-0410-961f-82ee72b054a4