predict.c (test_prediction_value_range): Use -1U instead of -1 to avoid narrowing conversion warning.

	* predict.c (test_prediction_value_range): Use -1U instead of -1
	to avoid narrowing conversion warning.
	* dumpfile.c (dump_options): Wrap all value into dump_flags_t cast
	to avoid narrowing conversion warning.
	* opt-functions.awk (var_ref): Return (unsigned short) -1 instead of
	-1.
	* optc-gen.awk (END): Expect (unsigned short) -1 instead of -1.

From-SVN: r249683