Fixed compile error in mysql_client_test using gcc

tests/mysql_client_fw.c

@@ -1190,7 +1190,7 @@ and you are welcome to modify and redistribute it under the GPL license\n");
 }
 
 
-struct my_tests_st *get_my_tests();  /* Will be defined in main .c file */
+static struct my_tests_st *get_my_tests();  /* To be defined in main .c file */
 
 static struct my_tests_st *my_testlist= 0;