cpplib.h (struct cpp_options): Add warn_cxx_operator_names field.

libcpp/:
	* include/cpplib.h (struct cpp_options): Add
	warn_cxx_operator_names field.
	(NODE_WARN_OPERATOR): Define.
	(struct cpp_hashnode): Increase flags field to 10 bits, decrease
	type to 6 bits.
	* init.c (mark_named_operators): Add flags parameter.
	(cpp_post_options): Pick flags value to pass to
	mark_named_operators.
	* lex.c (lex_identifier): If NODE_WARN_OPERATOR is set, warn that
	identifier is an operator name in C++.
gcc/:
	* fold-const.c (fold_unary): Rename local variable and to
	and_expr.
	* c-opts.c (c_common_handle_option): For -Wc++-compat set
	cpp_opts->warn_cxx_operator_names.
gcc/testsuite/:
	* gcc.dg/Wcxx-compat-13.c: New testcase.

From-SVN: r148438