Avoid warnings.
diff --git a/apps/gendh.c b/apps/gendh.c
index e5cb646..3d50948 100644
--- a/apps/gendh.c
+++ b/apps/gendh.c
@@ -193,7 +193,7 @@
 	if (p == 2) c='*';
 	if (p == 3) c='\n';
 	BIO_write((BIO *)arg,&c,1);
-	BIO_flush((BIO *)arg);
+	(void)BIO_flush((BIO *)arg);
 #ifdef LINT
 	p=n;
 #endif