stor-layout.c (update_alignment_for_field): Correct handling of unnamed bitfields on PCC_BITFIELD_TYPE_MATTERS machines.

	* stor-layout.c (update_alignment_for_field): Correct handling of
	unnamed bitfields on PCC_BITFIELD_TYPE_MATTERS machines.
	* doc/tm.texi (PCC_BITFIELD_TYPE_MATTERS): Note that an unnamed
	bitfield does not affect alignment.

	* testsuite/gcc.dg/i386-bitfield3.c: New test.

From-SVN: r60439