* emacs.c (my_heap_start, heap_bss_diff, MAX_HEAP_BSS_DIFF):
New variables and constant.
(main): Calculate heap_bss_diff. If we are dumping and the
heap_bss_diff is greater than MAX_HEAP_BSS_DIFF, set PER_LINUX32
and exec ourself again.
(Fdump_emacs): If heap_bss_diff is greater than MAX_HEAP_BSS_DIFF
print a warning.
* lastfile.c: Make my_endbss and my_endbss_static available on all
platforms.