coturn: allow to bind to ports below 1024

In some cases (corporate firewalls, hospitals) it may be desirable to
have a TURN service on 443 because this is open in every case.

To allow that, allow the turnserver to bind to ports below 1024.

srcpkgs/coturn/INSTALL

@@ -0,0 +1,5 @@
+case "${ACTION}" in
+post)
+	setcap CAP_NET_BIND_SERVICE=+ep usr/bin/turnserver
+	;;
+esac

srcpkgs/coturn/template

@@ -1,7 +1,7 @@
 # Template file for 'coturn'
 pkgname=coturn
 version=4.6.0
-revision=1
+revision=2
 build_style=configure
 configure_args="
  --prefix=/usr