diff --git a/src/interfaces/ecpg/preproc/output.c b/src/interfaces/ecpg/preproc/output.c
index 8e434e18f3..04379aebf3 100644
--- a/src/interfaces/ecpg/preproc/output.c
+++ b/src/interfaces/ecpg/preproc/output.c
@@ -87,7 +87,11 @@ char *
 hashline_number(void)
 {
 	/* do not print line numbers if we are in debug mode */
-	if (input_filename && !yydebug)
+	if (input_filename
+#ifdef YYDEBUG
+		&& !yydebug
+#endif
+		)
 	{
 		char	   *line = mm_alloc(strlen("\n#line %d \"%s\"\n") + 21 + strlen(input_filename));