Now we don't take any mutexes when creating or dropping internal HEAP tables during SELECT.
Change buffer sizes to size_t to make keycache 64 bit safe on platforms where sizeof(ulong) != sizeof(size_t)


BitKeeper/etc/ignore:
  added support-files/mysqld_multi.server
include/heap.h:
  Added 'internal_table' to HP_CREATE_INFO
include/keycache.h:
  Change buffer sizes to size_t to make keycache 64 bit safe
include/my_base.h:
  Added HA_OPEN_INTERNAL_TABLE to mark temporary tables that should be deleted on close
mysys/mf_keycache.c:
  Change buffer sizes to size_t to make keycache 64 bit safe
sql/sql_select.cc:
  Added HA_OPEN_INTERNAL_TABLE to mark temporary tables that should be deleted on close
  Removed not anymore needed call to delete_table()
storage/heap/ha_heap.cc:
  Added support for internal temporary tables that should be deleted on close.
  Internal tables now use dedicated open and close calls to avoid taking mutexes.
  If heap_open() failes, now delete the newly created table. (This fixes a possible memory leak)
  Remove never executed info() in create()
storage/heap/ha_heap.h:
  Added slots needed to handle internal temporary tables
storage/heap/heapdef.h:
  Protect against C++ inclusion
storage/heap/hp_close.c:
  Don't call list_delete() for internal temporary tables (They are not in the list)
storage/heap/hp_create.c:
  Added HP_SHARE ** element to heap_create() to store the SHARE of the newly created table.
  For internal temporary tables: Don't take any mutex and don't put them into the open table list.
storage/heap/hp_open.c:
  Split heap_open() into sub functions to be able to create internal temporary tables without putting them in the heap_share_list.
  Add faster open() functions for when we already know the 'share'.
storage/heap/hp_test1.c:
  Update call to heap_create()
  Initialize all keyinfo members.
storage/heap/hp_test2.c:
  Update call to heap_create()