linux64.h (SUBSUBTARGET_OVERRIDE_OPTIONS): Choose MASK_ALIGN_NATURAL if rs6000_alignm...

linux64.h (SUBSUBTARGET_OVERRIDE_OPTIONS): Choose MASK_ALIGN_NATURAL if rs6000_alignment_string not given.

	* config/rs6000/linux64.h (SUBSUBTARGET_OVERRIDE_OPTIONS): Choose
	MASK_ALIGN_NATURAL if rs6000_alignment_string not given.  Don't
	assign DEFAULT_ABI.
	(ADJUST_FIELD_ALIGN, ROUND_TYPE_ALIGN): Update comment.
	* config/rs6000/rs6000.c: Formatting.
	(rs6000_parse_alignment_option): Only set rs6000_alignment_flags
	when rs6000_alignment_string given.

From-SVN: r72431