diff --git a/builds/unix/configure.raw b/builds/unix/configure.raw
index 413d980..e7a4026 100644
--- a/builds/unix/configure.raw
+++ b/builds/unix/configure.raw
@@ -495,6 +495,8 @@
 AC_SUBST([SYSTEM_ZLIB])
 
 
+AC_LIBTOOL_WIN32_DLL
+
 AC_PROG_LIBTOOL
 # urgh -- these are internal libtool variables...
 AC_SUBST([enable_shared])