Merge 4.1 into 5.0 (first pass).

include/mysql_com.h

@@ -123,6 +123,8 @@ enum enum_server_command
 #define NET_WRITE_TIMEOUT	60		/* Timeout on write */
 #define NET_WAIT_TIMEOUT	8*60*60		/* Wait for new query */
 
+#define ONLY_KILL_QUERY         1
+
 struct st_vio;					/* Only C */
 typedef struct st_vio Vio;