rtl.h (read_rtx): Change prototype.

	* rtl.h (read_rtx): Change prototype.
	* read-rtl.c (read_rtx): Provide the caller with both an rtx and a
	line number.  Return true on success.
	* gensupport.c (process_include, init_md_reader_args_cb): Adjust
	callers accordingly.

From-SVN: r86657