Auto-generate the version information of Doxygen documentation
diff --git a/configure.ac b/configure.ac
index 0ee8aa6..b95c8cc 100644
--- a/configure.ac
+++ b/configure.ac
@@ -121,4 +121,8 @@
 	tests/ussd/Makefile
 	tests/smscb/Makefile
 	utils/Makefile
+	Doxyfile
+	Doxyfile.gsm
+	Doxyfile.vty
+	Doxyfile.codec
 	Makefile)