Backport of the keycache changes from http://lists.mysql.com/commits/31517 to make keycache 64-bit safe in 5.0. This is for bug #5731.


include/keycache.h:
  Backport of the keycache changes from http://lists.mysql.com/commits/31517 to make keycache 64-bit safe in 5.0.
mysys/mf_keycache.c:
  Backport of the keycache changes from http://lists.mysql.com/commits/31517 to make keycache 64-bit safe in 5.0.