* subsegs.c (subseg_change, subseg_get): Use xcalloc rather than

	xmalloc, memset.  Don't bother assigning NULL to known zero mem.
	(subseg_set_rest): Remove unnecessary cast.
	* write.c: Include libbfd.h.  Replace PTR with void * throughout.
	Remove unnecessary forward declarations and casts.
	(set_symtab): Delete extern bfd_alloc.
	(fixup_segment): Move.