add git-version-gen to auto-generate version from git repo tags
diff --git a/configure.ac b/configure.ac
index 1208025..70d9f5d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,5 +1,6 @@
 AC_PREREQ([2.65])
-AC_INIT([gapk], [0.1], [main@lists.airprobe.org])
+AC_INIT([gapk],
+	m4_esyscmd([./git-version-gen .tarball-version]), [main@lists.airprobe.org])
 
 AM_INIT_AUTOMAKE([dist-bzip2])