* cpplex.c (handle_newline, skip_escaped_newlines,
	get_effective_char, skip_block_comment, skip_line_comment,
	parse_identifier_slow, parse_number, parse_string,
	_cpp_lex_direct): Update to do more stepping back.
	(trigraph_ok): Similarly.  Rename trigraph_p.
	(SAVE_STATE, RESTORE_STATE): Remove.
	(BUFF_SIZE_UPPER_BOUND): Tweak.  Add sanity check.

	* cpplib.c (destringize): Rename destringize_and_run, and
	call run_directive directly.
	(_cpp_do__Pragma): Simplify.

From-SVN: r46373