--- misc/cppunit-1.12.1/include/cppunit/plugin/TestPlugIn.h	2010-01-11 14:42:25.084658287 +0100
+++ misc/build/cppunit-1.12.1/include/cppunit/plugin/TestPlugIn.h	2010-01-11 14:42:18.660706180 +0100
@@ -149,6 +149,9 @@
 #define NOMINMAX
 #define BLENDFUNCTION void    // for mingw & gcc
 #include <windows.h>
+#if defined(OPTIONAL) // set within windows.h
+#undef OPTIONAL
+#endif
 #endif
 #define CPPUNIT_PLUGIN_IMPLEMENT_MAIN()               \
   BOOL APIENTRY DllMain( HANDLE, DWORD, LPVOID )      \