--- gavl-1.4.0/configure.ac	2017-10-29 22:50:32.707720400 -0400
+++ gavl-1.4.0/configure.ac	2017-10-29 22:50:54.984191200 -0400
@@ -32,6 +32,7 @@
 AC_DISABLE_STATIC
 
 AC_PROG_LIBTOOL
+AC_LIBTOOL_WIN32_DLL
 AM_PROG_LIBTOOL
 
 AC_PROG_MAKE_SET