Merge pull request #6569 from rafaeldtinoco/master

MySQL 8 integration requires previous declaration checks

libs/libmysqlxx/include/mysqlxx/Types.h

@@ -3,6 +3,8 @@
 #include <cstdint>
 #include <string>
 
+#ifndef _mysql_h
+
 struct st_mysql;
 using MYSQL = st_mysql;
 
@@ -14,7 +16,7 @@ using MYSQL_ROW = char**;
 struct st_mysql_field;
 using MYSQL_FIELD = st_mysql_field;
 
-
+#endif
 
 namespace mysqlxx
 {