mysql5.5: add workaround for GCC 4.7 and MySQL 5.5.22

MySQL 5.5.22 uses deprecated MYSQL::generate_name style in class
definition.

fixes #1337

Reported by Kazuhiko Shiozaki. Thanks!!!

configure.ac

@@ -74,6 +74,9 @@ if test "$GCC" = "yes"; then
   CHECK_BUILD_FLAG([-Wextra])
   CHECK_BUILD_FLAG([-Wno-unused-parameter])
   CHECK_BUILD_FLAG([-Wno-strict-aliasing])
+  # REMOVEME: workaround for MySQL/MariaDB 5.5.22 :<
+  # They uses deprecated MYSQL::generate_name style in class definition.
+  CHECK_BUILD_FLAG([-Wno-deprecated])
 fi
 
 standalone_build=