c-common.c (maybe_warn_bool_compare): When comparing with 0/1, require that the non-constant be of a boolean type.

	* c-common.c (maybe_warn_bool_compare): When comparing with 0/1,
	require that the non-constant be of a boolean type.

	* c-c++-common/Wbool-compare-3.c: New test.

From-SVN: r222622