Fixed compiler error in slave.cc on some platforms.

BitKeeper/deleted/.del-libmysqld.def~8edf7b8780ce943c:
  Delete: VC++Files/libmysqld/libmysqld.def
sql/slave.cc:
  Fix to modify tmp_buf instead of buf, which is a const char *

VC++Files/libmysqld/libmysqld.def

-LIBRARY		LIBMYSQLD
-DESCRIPTION	'MySQL 4.0 Embedded Server Library'
-VERSION		4.0
-EXPORTS
-	mysql_server_end
-	mysql_server_init
-	mysql_use_result
-	mysql_thread_safe
-	mysql_thread_id
-	mysql_store_result
-	mysql_stat
-	mysql_shutdown
-	mysql_select_db
-	mysql_row_tell
-	mysql_row_seek
-	mysql_real_query
-	mysql_real_connect
-	mysql_query
-	mysql_ping
-	mysql_options
-	mysql_num_rows
-	mysql_num_fields
-	mysql_list_tables
-	mysql_list_processes
-	mysql_list_fields
-	mysql_list_dbs
-	mysql_kill
-	mysql_insert_id
-	mysql_init
-	mysql_info
-	mysql_get_server_info
-	mysql_get_proto_info
-	mysql_get_host_info
-	mysql_get_client_info
-	mysql_free_result
-	mysql_field_tell
-	mysql_field_count
-	mysql_field_seek
-	mysql_fetch_row
-	mysql_fetch_lengths
-	mysql_fetch_fields
-	mysql_fetch_field_direct
-	mysql_fetch_field
-	mysql_escape_string
-	mysql_real_escape_string
-	mysql_error
-	mysql_errno
-	mysql_eof
-	mysql_dump_debug_info
-	mysql_drop_db
-	mysql_debug
-	mysql_data_seek
-	mysql_create_db
-	mysql_character_set_name
-	mysql_change_user
-	mysql_connect
-	mysql_close
-	mysql_affected_rows
-	mysql_thread_init
-	mysql_thread_end
-	mysql_send_query
-	mysql_read_query_result
-	mysql_refresh
-	mysql_odbc_escape_string
-	myodbc_remove_escape

sql/slave.cc

@@ -3052,8 +3052,8 @@ static int queue_old_event(MASTER_INFO *mi, const char *buf,
       this end 0, which leads to segfault.
     */
     tmp_buf[event_len++]=0;
+    int4store(tmp_buf+EVENT_LEN_OFFSET, event_len);
     buf = (const char*)tmp_buf;
-    int4store(buf+EVENT_LEN_OFFSET, event_len);
   }
   /*
     This will transform LOAD_EVENT into CREATE_FILE_EVENT, ask the master to