deb/rpm: build with --enable-gtp-linux

Allow optional use of the GTP kernel module.

Related: OS#3208
Change-Id: Ic001ec6c5ec9887706a5b27f2a48cd61942ab4ee
diff --git a/debian/control b/debian/control
index 0822773..1fd1937 100644
--- a/debian/control
+++ b/debian/control
@@ -8,7 +8,8 @@
                libdpkg-perl, git,
                dh-autoreconf,
                libosmocore-dev (>= 1.4.0),
-               osmo-gsm-manuals-dev
+               osmo-gsm-manuals-dev,
+               libgtpnl-dev (>= 1.2.0)
 Standards-Version: 3.9.6
 Vcs-Browser: http://git.osmocom.org/osmo-ggsn/
 Vcs-Git: git://git.osmocom.org/osmo-ggsn