Dsiable udf.test waiting for a check wheter udf_example.so exists

mysql-test/include/have_udf.inc:
  Add comment that a check for udf_example.so must be made
mysql-test/t/disabled.def:
  Disable udf.test

mysql-test/include/have_udf.inc

@@ -6,3 +6,9 @@
 disable_query_log;
 show variables like "have_dlopen";
 enable_query_log;
+
+#
+# Check that the "udf_example.so" file has been created
+#
+
+# TODO

mysql-test/t/disabled.def

@@ -43,3 +43,4 @@ rpl_sp                  : Bug#16456
 rpl_until               : Unstable test case, bug#15886
 sp-goto                 : GOTO is currently is disabled - will be fixed in the future
 mysqldump               : BUG#18078
+udf			: Need to check if udf_example.so has been built