configure.ac: Use git-version-gen to set VERSION

Change-Id: Id6535719321c8bb690936b5ae3ddcb9d8a9aa4d7
diff --git a/configure.ac b/configure.ac
index 19e07b2..f7580e6 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,6 +1,8 @@
 dnl Process this file with autoconf to create configure.
 
-AC_INIT([libgtpnl], [1.1.0])
+AC_INIT([libgtpnl],
+	m4_esyscmd([./git-version-gen .tarball-version]),
+	[osmocom-net-gprs@lists.osmocom.org])
 AC_CONFIG_AUX_DIR([build-aux])
 AC_CANONICAL_HOST
 AC_CONFIG_MACRO_DIR([m4])