(output_init_element): Call digest_init before calling output_constant.
(output_init_element): Call digest_init before
calling output_constant. Always pass 0, 0 for last 2 args
to digest_init.
(build_binary_op): Warn about ordered comparison
between pointers to complete and incomplete types.
(digest_init): No error for a STRING_CST that already
went through digest_init.
(parser_build_binary_op): Generate a NON_LVALUE_EXPR, not NOP_EXPR,
around a constant value.