consistent Doxyfile naming
diff --git a/configure.ac b/configure.ac
index a77e3e8..ef4b0aa 100644
--- a/configure.ac
+++ b/configure.ac
@@ -124,7 +124,7 @@
 	tests/ussd/Makefile
 	tests/smscb/Makefile
 	utils/Makefile
-	Doxyfile
+	Doxyfile.core
 	Doxyfile.gsm
 	Doxyfile.vty
 	Doxyfile.codec