* cppexp.c (struct op): Add token pointer.
	(check_promotion, CHECK_PROMOTION): New.
	(optab): Update.
	(_cpp_parse_expr): Update, use token pointer of struct op.
	(reduce): Warn about change of sign owing to promotion.
	* cppinit.c (cpp_handle_option): New warning if -Wall.
	* cpplib.h (struct cpp_options): New member.
testsuite:
	* gcc.dg/cpp/Wsignprom.c: New tests.

From-SVN: r55611