* ieee.c (struct ieee_defined_enum): Add defined field.

	* ieee.c (struct ieee_defined_enum): Add defined field.
	(ieee_enum_type): If the enum tag has been seen before but not
	defined, reuse the same type index, and define it.
	(ieee_tag_type): If this enum has not been defined, add an
	undefined entry to the list of enums.
PR 10946.