- Jean-Francois Bertrand reported a libcurl crash with CURLOPT_TCP_NODELAY

since libcurl used getprotobyname() and that isn't thread-safe. We now
  switched to use IPPROTO_TCP unconditionally, but perhaps the proper fix is
  to detect the thread-safe version of the function and use that.
  http://curl.haxx.se/mail/lib-2008-05/0011.html

lib/connect.c

@@ -685,7 +685,14 @@ static void tcpnodelay(struct connectdata *conn,
   socklen_t onoff = (socklen_t) data->set.tcp_nodelay;
   int proto = IPPROTO_TCP;
 
-#ifdef HAVE_GETPROTOBYNAME
+#if 0
+  /* The use of getprotobyname() is disabled since it isn't thread-safe on
+     numerous systems. On these getprotobyname_r() should be used instead, but
+     that exists in at least one 4 arg version and one 5 arg version, and
+     since the proto number rarely changes anyway we now just use the hard
+     coded number. The "proper" fix would need a configure check for the
+     correct function much in the same style the gethostbyname_r versions are
+     detected. */
   struct protoent *pe = getprotobyname("tcp");
   if(pe)
     proto = pe->p_proto;