- Make initialization of the message buffer a little less magic-looking.
- Maintain two copies of the number and size of physical memory segments.
One copy, mem_clusters[], contains _all_ of physical RAM, for crash dumps.
The other copy, phys_seg_list[], starts out with all of physical RAM (and
is used to initialize mem_clusters[]), but is adjusted to be the memory
actually managed by the VM system.
- Fix crash dumps with regard to multiple memory segments.