SLES10 Fixes (part 6)

SLES10 Fixes (part 6)
- Prior to 2.6.17 there were no *_pgdat helper functions in mm/mmzone.c.
  Instead for_each_zone() operated directly on pgdat_list which may or
  may not have been exported depending on how your kernel was compiled.
  Now new configure checks determine if you have the helpers or not, and
  if the needed symbols are exported.  If they are not exported then they
  are dynamically aquired at runtime by kallsyms_lookup_name().