os2: integrate the port into main tree.

test/testnative.c

@@ -31,6 +31,9 @@ static NativeWindowFactory *factories[] = {
 #endif
 #ifdef TEST_NATIVE_COCOA
     &CocoaWindowFactory,
+#endif
+#ifdef TEST_NATIVE_OS2
+    &OS2WindowFactory,
 #endif
     NULL
 };