zerotier: update to 1.6.2

Signed-off-by: Moritz Warning <moritzwarning@web.de>

net/zerotier/patches/0007-add-cerrno-header-for-str-errno.patch

@@ -0,0 +1,28 @@
+From e06177a74f1e4314baf17c52f360dabcb78e69cd Mon Sep 17 00:00:00 2001
+From: Moritz Warning <moritzwarning@web.de>
+Date: Sun, 29 Nov 2020 19:45:36 +0100
+Subject: [PATCH 7/8] add cerrno header for (str)errno
+
+Fixes compilation under libcxx.
+
+Signed-off-by: Rosen Penev <rosenp@gmail.com>
+---
+ osdep/LinuxNetLink.cpp | 2 ++
+ 1 file changed, 2 insertions(+)
+
+diff --git a/osdep/LinuxNetLink.cpp b/osdep/LinuxNetLink.cpp
+index 421da1f6..b7c13edf 100644
+--- a/osdep/LinuxNetLink.cpp
++++ b/osdep/LinuxNetLink.cpp
+@@ -22,6 +22,8 @@
+ #include <unistd.h>
+ #include <linux/if_tun.h>
+ 
++#include <cerrno>
++
+ #ifndef IFNAMSIZ
+ #define IFNAMSIZ 16
+ #endif
+-- 
+2.29.2
+