ha_innodb.cc:

  Make the drop InnoDB database operation aware of the setting FOREIGN_KEY_CHECKS=0; DROP DATABASE seems to work ok anyway, but that is because MySQL first calls DROP TABLE for each table which has an .frm file

sql/ha_innodb.cc

@@ -3687,6 +3687,10 @@ innobase_drop_database(
 	trx->mysql_thd = current_thd;
 	trx->mysql_query_str = &((*current_thd).query);
 
+	if (current_thd->options & OPTION_NO_FOREIGN_KEY_CHECKS) {
+		trx->check_foreigns = FALSE;
+	}
+
   	error = row_drop_database_for_mysql(namebuf, trx);
 
 	/* Flush the log to reduce probability that the .frm files and