c-lex.c: Sync with C++ frontend.

c-lex.c: Sync with C++ frontend.

	* c-lex.c: Sync with C++ frontend.
	(linemode): New variable.
	(parse_float): imag, conversion_errno, and type are output only.
	(yylex): Adjust.  Move initial '.' case into main switch.
	Use linemode.
	(handle_generic_pragma): Just deal with tokens.
	(readescape): Use ISXDIGIT and ISGRAPH.
	* c-parse.in: Add END_OF_LINE token.

	* c-lex.c (lang_init): Generalize.
	(nextchar): Remove.  Replace uses with UNGETC.
	(skip_white_space): Handle linemode here.  Optimize for cpplib.
	(skip_white_space_on_line): Remove.
	(extend_token_buffer_to): New fn.
	(extend_token_buffer): Use it.
	(read_line_number, check_newline): Just deal with tokens.
	(token_getch, token_put_back): New fns.
	(yylex): Use them.  More cpplib optimizations.  Simplify.

	* c-lex.c (init_parse): Set cpp_token to CPP_DIRECTIVE.
	(consume_string): Make this smart about USE_CPPLIB.
	(check_newline): Rewrite to be intelligent about USE_CPPLIB.
	(yylex): Rewrite to be intelligent about USE_CPPLIB.
	Also, clean up cases where we redundantly set token_buffer[0].
	(read_line_number): New fn.
	(ignore_escape_flag): New variable.

From-SVN: r28507