(mark_object): Don't mark symbol names in pure space.
(gc_sweep): Don't unmark symbol names in pure space.
(toplevel): Include setjmp.h.
(PURE_POINTER_P): New define.
(enum mem_type) [GC_MARK_STACK]: New enumeration.
(Vdead) [GC_MARK_STACK]: New variable.
(lisp_malloc): Add parameter TYPE, call mem_insert if
GC_MARK_STACK is defined.
(allocate_buffer): New function.
(lisp_free) [GC_MARK_STACK]: Call mem_delete.
(free_float) [GC_MARK_STACK]: Set type to Vdead.
(free_cons) [GC_MARK_STACK]: Set car to Vdead.
(stack_base, mem_root, mem_z) [GC_MARK_STACK]: New variables.
(MEM_NIL) [GC_MARK_STACK]: New define.
(struct mem_node) [GC_MARK_STACK]: New structure.
(mem_init, mem_find, mem_insert, mem_delete, mem_insert_fixup)
(mem_delete_fixup, mem_rotate_left, mem_rotate_right)
(live_string_p, live_cons_p, live_symbol_p, live_float_p)
(live_misc_p, live_vector_p, live_buffer_p, mark_memory)
(mark_stack) [GC_MARK_STACK]: New functions.
(Fgarbage_collect) [GC_MARK_STACK]: Call mark_stack.
(clear_marks): Removed.
(gc_sweep): Set free conses' car, free floats' type, free
symbols' function to Vdead. Use lisp_free to free buffers.
(init_alloc_once): Initialize Vdead.
(survives_gc_p): Return non-zero for pure objects.