* cppexp.c (lex): Update to use state.skip_eval.
	(struct op): Remove prio and flags members.
	(FLAG_BITS, FLAG_MASK, PRIO_SHIFT, EXTRACT_PRIO, EXTRACT_FLAGS,
	SHORT_CIRCUIT, RIGHT_ASSOC, ..._PRIO, op_to_prio): Remove.
	(LEFT_ASSOC): New macro.
	(optab): New table of operator priorities and flags.
	(SHIFT): Update.
	(_cpp_parse_expr): Clean up logic.  Return bool.  Use a
	malloc-ed parser stack.
	(reduce): New; reduce the operator stack.
	(_cpp_expand_op_stack): Expand the operator stack as necessary.
	* cpphash.h (struct op): Predeclare.
	(struct cpp_reader): New members op_stack, op_limit.
	(struct lexer_state): New member skip_eval.
	(_cpp_parse_expr): Update.
	(_cpp_expand_op_stack): New.
	* cpplib.c (do_if): Update.
	* cppinit.c (cpp_create_reader): Create op stack.
	(cpp_destroy): And destroy it.
	* cpplib.h (CPP_LAST_CPP_OP): Correct.
	(TTYPE_TABLE): Correct.
testsuite:
	* gcc.dg/cpp/if-mop.c: Update.
	* gcc.dg/cpp/if-mpar.c: Add test.
	* gcc.dg/cpp/if-oppr.c: Update.

From-SVN: r52853