Use release helper from libosmocore

Change-Id: I3b22a026ee61e88ed6d785182990cfcba0487bfe
Related: OS#1861
diff --git a/Makefile.am b/Makefile.am
index cb72faf..deb3299 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -9,3 +9,5 @@
 pkgconfig_DATA = libgtpnl.pc
 
 ${pkgconfig_DATA}: ${top_builddir}/config.status
+
+@RELMAKE@
diff --git a/configure.ac b/configure.ac
index 459fab1..15eb998 100644
--- a/configure.ac
+++ b/configure.ac
@@ -13,6 +13,10 @@
 dnl Dependencies
 PKG_CHECK_MODULES([LIBMNL], [libmnl >= 1.0.0])
 
+dnl include release helper
+RELMAKE='-include osmo-release.mk'
+AC_SUBST([RELMAKE])
+
 AC_PROG_CC
 AM_PROG_CC_C_O
 AC_EXEEXT