Merge MySQL 5.1.46 into MariaDB.

Still two test failures to be solved: main.myisam and main.subselect.

mysys/my_init.c

@@ -166,6 +166,7 @@ void my_end(int infoflag)
       my_print_open_files();
     }
   }
+  free_charsets();
   my_error_unregister_all();
   my_once_free();
 #ifdef THREAD