1 // { dg-do preprocess }
2 // { dg-options "-std=gnu99 -fdiagnostics-show-option -Werror=undef" }
3 /* { dg-message "some warnings being treated as errors" "" {target "*-*-*"} 0 } */
4 #if x // { dg-error "\"x\" is not defined .-Werror=undef." }
5 #endif
6