uhttpd: fix TCP_FASTOPEN related compile error

Fixes [1]:

  .../uhttpd-a8bf9c00842224edb394e79909053f7628ee6a82/listen.c: In function 'uh_setup_listeners':
  .../uhttpd-a8bf9c00842224edb394e79909053f7628ee6a82/listen.c:120:30: error: 'TCP_FASTOPEN' undeclared (first use in this function)

[1] http://autobuild.buildroot.net/results/56e/56e0727ccd1255b05e03d1b79dc238bd88701230

Signed-off-by: Peter Seiderer <ps.report@gmx.net>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/uhttpd/0002-Fix-TCP_FASTOPEN-related-compile-error.patch

@@ -0,0 +1,30 @@
+From adbab70d3602d77736781be344cfdc5508cb0600 Mon Sep 17 00:00:00 2001
+From: Peter Seiderer <ps.report@gmx.net>
+Date: Mon, 3 Apr 2017 19:22:30 +0200
+Subject: [PATCH] Fix TCP_FASTOPEN related compile error.
+
+Signed-off-by: Peter Seiderer <ps.report@gmx.net>
+---
+ listen.c | 6 ++++++
+ 1 file changed, 6 insertions(+)
+
+diff --git a/listen.c b/listen.c
+index 2a54888..4dabe34 100644
+--- a/listen.c
++++ b/listen.c
+@@ -96,6 +96,12 @@ static void listener_cb(struct uloop_fd *fd, unsigned int events)
+ 		uh_block_listener(l);
+ }
+ 
++#ifdef linux
++#ifndef TCP_FASTOPEN
++#define TCP_FASTOPEN 23
++#endif
++#endif
++
+ void uh_setup_listeners(void)
+ {
+ 	struct listener *l;
+-- 
+2.11.0
+