PR c/68062
	* c-typeck.c (build_binary_op) [EQ_EXPR, GE_EXPR]: Promote operand
	to unsigned, if needed.  Add -Wsign-compare warning.

	* typeck.c (cp_build_binary_op): Promote operand to unsigned, if
	needed.  Add -Wsign-compare warning.

	* c-c++-common/vector-compare-4.c: New test.

From-SVN: r232894