diff --git a/configure.ac b/configure.ac
index 5fa5832..fd2f1f4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -4,8 +4,14 @@ AM_INIT_AUTOMAKE([foreign])
 AM_CONFIG_HEADER(config.h)
 AM_CONFIG_HEADER(poppler/poppler-config.h)
 
-dnl ##### Checks for programs.
+dnl ##### Initialize libtool.
+# with old deprecated syntax:
+AC_LIBTOOL_WIN32_DLL
 AC_PROG_LIBTOOL
+# with new syntax (requires recent libtool):
+#LT_INIT([win32-dll])
+
+dnl ##### Checks for programs.
 AC_PROG_CC
 AC_PROG_CXX
 AC_ISC_POSIX