Update of query cache code.

Changed some sql_alloc() -> thd->alloc()
Removed a lot of compiler warnings on Linux Alpha (64 bit)
Fixed some core dumps on 64 bit systems (wrong type for packet_len)


Docs/manual.texi:
  Added base information about the query cache.
include/hash.h:
  Export hash_replace
include/myisam.h:
  Update of query cache code
libmysql/net.c:
  Add casts to make things safe on 64 bit systems.
myisam/mi_write.c:
  Update of query cache code
myisammrg/myrg_extra.c:
  Update of query cache code
mysys/hash.c:
  Added safety check to hash_replace
sql/field.cc:
  Removed compiler warnings.
sql/field.h:
  Removed compiler warnings
sql/ha_myisam.cc:
  Fixed wrong type of packet_len
sql/item.h:
  Remove warnings
sql/log_event.cc:
  Cleanup
sql/log_event.h:
  Cleanup to make code more readable
sql/mf_iocache.cc:
  Fixed wrong type
sql/mysql_priv.h:
  Update of query cache code
sql/mysqld.cc:
  Update of query cache code
sql/net_serv.cc:
  Remove compiler warnings
sql/opt_range.h:
  Remove compiler warnings
sql/sql_cache.cc:
  Update of query cache code
sql/sql_cache.h:
  Update of query cache code
sql/sql_class.h:
  Cleanup
sql/sql_insert.cc:
  Use thd->alloc() instead of sql_alloc()
sql/sql_parse.cc:
  Fixed compiler warnings.
  Changed some sql_alloc() -> thd->alloc()
sql/sql_select.cc:
  Changed sql_alloc() -> thd_alloc()
sql/sql_select.h:
  Faster alloc()
sql/sql_show.cc:
  Update of query cache code
sql/sql_table.cc:
  Faster alloc()
sql/table.cc:
  Faster alloc()

sql/opt_range.h

@@ -48,9 +48,9 @@ class QUICK_RANGE :public Sql_alloc {
 	      uint flag_arg)
     : min_key((char*) sql_memdup(min_key_arg,min_length_arg+1)),
       max_key((char*) sql_memdup(max_key_arg,max_length_arg+1)),
-      min_length(min_length_arg),
-      max_length(max_length_arg),
-      flag(flag_arg)
+      min_length((uint16) min_length_arg),
+      max_length((uint16) max_length_arg),
+      flag((uint16) flag_arg)
     {}
 };