Use AC_PROG_LIBTOOL
diff --git a/configure.ac b/configure.ac
index c841ba4..205cffd 100644
--- a/configure.ac
+++ b/configure.ac
@@ -5,9 +5,9 @@
 
 AC_CONFIG_HEADERS([config.h])
 AM_MAINTAINER_MODE
-AC_PROG_CXX
-AC_PROG_RANLIB
 AM_PROG_AR
+AC_PROG_LIBTOOL
+AC_PROG_CXX
 AM_PROG_CC_C_O
 AC_LANG([C++])