InnoDB: make UNIV_SYNC_DEBUG useable again

innobase/include/sync0sync.h:
  mutex_get_debug_info(): add const qualifier
innobase/srv/srv0start.c:
  Set srv_monitor_file_mutex at level SYNC_NO_ORDER_CHECK
innobase/sync/sync0arr.c:
  sync_array_detect_deadlock(): Remove extraneous declaration of "lock"
innobase/sync/sync0sync.c:
  mutex_get_debug_info(): add const qualifier

innobase/include/sync0sync.h

@@ -218,7 +218,7 @@ void
 mutex_get_debug_info(
 /*=================*/
 	mutex_t*	mutex,		/* in: mutex */
-	char**		file_name,	/* out: file where requested */
+	const char**	file_name,	/* out: file where requested */
 	ulint*		line,		/* out: line where requested */
 	os_thread_id_t* thread_id);	/* out: id of the thread which owns
 					the mutex */

innobase/srv/srv0start.c

@@ -1022,6 +1022,7 @@ NetWare. */
 	}
 
 	mutex_create(&srv_monitor_file_mutex);
+	mutex_set_level(&srv_monitor_file_mutex, SYNC_NO_ORDER_CHECK);
 	srv_monitor_file_name = mem_alloc(
 			strlen(fil_path_to_mysql_datadir) +
 			20 + sizeof "/innodb_status.");

innobase/sync/sync0arr.c

@@ -613,7 +613,6 @@ sync_array_detect_deadlock(
 	rw_lock_t*	lock;
 	os_thread_id_t	thread;
 	ibool		ret;
-	rw_lock_t*	lock;
 	rw_lock_debug_t*debug;
 	
         ut_a(arr && start && cell);

innobase/sync/sync0sync.c

@@ -515,7 +515,7 @@ void
 mutex_get_debug_info(
 /*=================*/
 	mutex_t*	mutex,		/* in: mutex */
-	char**		file_name,	/* out: file where requested */
+	const char**	file_name,	/* out: file where requested */
 	ulint*		line,		/* out: line where requested */
 	os_thread_id_t* thread_id)	/* out: id of the thread which owns
 					the mutex */
@@ -574,7 +574,7 @@ mutex_list_print_info(void)
 /*=======================*/
 {
 	mutex_t*	mutex;
-	char*		file_name;
+	const char*	file_name;
 	ulint		line;
 	os_thread_id_t	thread_id;
 	ulint		count		= 0;
@@ -772,7 +772,7 @@ sync_thread_levels_g(
 
 					if (mutex_get_lock_word(mutex) != 0) {
 #ifdef UNIV_SYNC_DEBUG
-						char*		file_name;
+						const char*	file_name;
 						ulint		line;
 						os_thread_id_t	thread_id;