Add patch from PR 43815 to fix build on some Linuces.

net/avahi/distinfo

@@ -1,4 +1,4 @@
-$NetBSD: distinfo,v 1.8 2010/07/24 13:42:12 obache Exp $
+$NetBSD: distinfo,v 1.9 2010/11/18 13:56:05 wiz Exp $
 
 SHA1 (avahi-0.6.27.tar.gz) = e763bbeba92fd5b3ba3e2af5fc85aaf99b406c8b
 RMD160 (avahi-0.6.27.tar.gz) = 36e6a242f0c926351e31871d8a4f8a52a501fdc3
@@ -8,6 +8,7 @@ SHA1 (patch-ab) = aca73131b1a1df97dab6f221c59bd5e21136f816
 SHA1 (patch-ac) = f506e4f7839ca7201abfc0fe22120993e9a2279d
 SHA1 (patch-ad) = 0777139388729f5a8a1aa8dffd602f3c34c9f61b
 SHA1 (patch-ae) = d0db18ff6c830da992510465df53d0bc0433d2a1
+SHA1 (patch-af) = c8d0ea175abfc25c5d55e51fc00cb86ecdb8574c
 SHA1 (patch-ag) = f729ef5b61ffaa641fe5abe78b42c4f6316569b7
 SHA1 (patch-ah) = 4b3ffdb927daef8c939527fd5c5893f9f88b3ff3
 SHA1 (patch-ai) = 406b314c8105e28cffb83a92bb80f2dc1b264c3f

net/avahi/patches/patch-af

@@ -0,0 +1,31 @@
+$NetBSD: patch-af,v 1.3 2010/11/18 13:56:05 wiz Exp $
+
+PR 43815:
+net/avahi fails on my Linux system:
+
+   ...
+     CC     avahi_daemon-sd-daemon.o
+   sd-daemon.c: In function 'sd_notify':
+   sd-daemon.c:356: error: 'SOCK_CLOEXEC' undeclared (first use in this function)
+   sd-daemon.c:356: error: (Each undeclared identifier is reported only once
+   sd-daemon.c:356: error: for each function it appears in.)
+   gmake[2]: *** [avahi_daemon-sd-daemon.o] Error 1
+
+This is because my glibc and Kernel is not modern enough for this
+version of avahi.
+
+http://avahi.org/ticket/316
+
+--- avahi-daemon/sd-daemon.c.orig	2010-07-13 00:45:20.000000000 +0000
++++ avahi-daemon/sd-daemon.c
+@@ -41,6 +41,10 @@
+ #include <stdarg.h>
+ #include <stdio.h>
+ 
++#if !defined(SOCK_CLOEXEC) && !defined(DISABLE_SYSTEMD)
++#define DISABLE_SYSTEMD 1
++#endif
++
+ #include "sd-daemon.h"
+ 
+ int sd_listen_fds(int unset_environment) {