* Reinstantiate ptmalloc3.
	* configure.ac (MALLOC_OFILES): Drop here.
	* configure: Regenerate.
	* Makefile.in (MALLOC_OFILES): Set to fixed value here.
	* cygmalloc.h (HAVE_MORECORE): Define.
	* malloc.cc (init_user_mstate): Don't disable MORECORE if building
	with ONLY_MSPACES.