diff --git a/io/iob_send.c b/io/iob_send.c
index 447ca53..10a6e8c 100644
--- a/io/iob_send.c
+++ b/io/iob_send.c
@@ -224,6 +224,9 @@ eagain:
 #ifdef MSG_ZEROCOPY
       static int nozerocopy;
       int dozerocopy=1;
+#else
+      const int nozerocopy=0;
+      const int dozerocopy=1;
 #endif
       if (nozerocopy && dozerocopy==0 && docork<0) {	/* write+writev */
 	if (headers==1)	/* cosmetics for strace */