From 8b0450cd29bfc1ced38510f2a86c089341a8dec1 Mon Sep 17 00:00:00 2001
From: leitner <leitner>
Date: Sun, 5 Apr 2020 20:19:25 +0000
Subject: [PATCH] some old glibc may define MSG_ZEROCOPY but not SO_ZEROCOPY
 :-(

---
 io/iob_send.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/io/iob_send.c b/io/iob_send.c
index 10a6e8c..ad13f09 100644
--- a/io/iob_send.c
+++ b/io/iob_send.c
@@ -234,7 +234,7 @@ eagain:
 	else
 	  sent=writev(s,v,headers);
       } else {
-#ifdef MSG_ZEROCOPY
+#if defined(MSG_ZEROCOPY) && defined(SO_ZEROCOPY)
 	  if (!nozerocopy && sum>=8*1024) {
 	    /* MSG_ZEROCOPY has page table management overhead,
 	     * it only pays off after 8k or so */