This directory implements a memory management library that hides the
operating system dependencies.  It supports the allocation of memory
objects aligned to MAP_PAGE_SZB byte boundries (see mapping.h).

The following routines are exported:
  void MEM_InitMemory ();
  mem_obj_t *MEM_AllocMemObj (word_t szb);
  void MEM_FreeMemObj (mem_obj_t *obj);

There are three different implementations:

  1) a version that uses the SVR4 mmap mechanism to allocate chunks of memory.

  2) a version that uses the MACH vm_allocate call to allocate chunks of memory.

  3) a version that layers memory chunk management on top of the brk system
     call.  This version also provides an implementation of malloc.

The version of malloc was retrieved from g.oswego.edu:/pub/misc/malloc.c
