This is required to allow key_buffer_size > 4 GB (bug #5731).


include/my_sys.h:
  Backport of my_malloc() changes from 5.1 to make it 64-bit safe on Unix platforms.
mysys/my_largepage.c:
  Backport of my_malloc() changes from 5.1 to make it 64-bit safe on Unix platforms.
mysys/my_malloc.c:
  Backport of my_malloc() changes from 5.1 to make it 64-bit safe on Unix platforms.
mysys/safemalloc.c:
  Backport of my_malloc() changes from 5.1 to make it 64-bit safe on Unix platforms.