if (PL_dowarn & G_WARN_ON)
goto context_info_warnings_on;
else
+#if SU_HAS_PERL(5, 17, 4)
+ mask = &PL_sv_undef;
+#else
goto context_info_warnings_off;
+#endif
} else if (old_warnings == pWARN_NONE) {
context_info_warnings_off:
mask = su_newmortal_pvn(WARN_NONEstring, WARNsize);