* gas/sb.c: Include as.h.

	* gas/sb.c: Include as.h.
	(sb_to_scrub, scrub_position, scrub_from_sb): New statics.
	(sb_scrub_and_add_sb): New interface.
	* gas/sb.h: Declare sb_scrub_and_add_sb.
	* gas/input-scrub.c (input_scrub_include_sb): Use it.

	* gas/config/tc-arm.c (do_t_arit3c): Correct typo in expression.
	(do_t_mul): Allow dest to equal either source1 or source2 in
	16-bit form; do not complain about dest == source1 in any
	case.

	* gas/testsuite/gas/arm/tcompat2.s: Test both dest==source1 and
	dest==source2 for commutative arithmetic instructions.
	* gas/testsuite/gas/arm/tcompat2.d: Update to match.
	* gas/testsuite/gas/arm/t16-bad.l: Adjust expected diagnostic.
	* gas/testsuite/gas/arm/macro1.s, gas/arm/macro1.d: New test pair.
	* gas/testsuite/gas/arm/arm.exp: Run it.