* gengtype.c (process_gc_options): Remove unnecessary forward decl.

	Add another out parameter, "skip".
	(set_gc_used_type): Adjust calls to process_gc_options.  If a field
	is tagged "skip", do not mark its type used.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@119034 138bc75d-0d04-0410-961f-82ee72b054a4