diff --git a/collects/mred/private/wx/platform.rkt b/collects/mred/private/wx/platform.rkt
index 14d6f126..2e067897 100644
--- a/collects/mred/private/wx/platform.rkt
+++ b/collects/mred/private/wx/platform.rkt
@@ -3,10 +3,14 @@
 (provide (all-defined-out))
 
 (define-runtime-path platform-lib
-  (case (system-type)
-    [(#;windows) '(lib "mred/private/wx/win32/platform.rkt")]
-    [(macosx) '(lib "mred/private/wx/cocoa/platform.rkt")]
-    [(windows unix) '(lib "mred/private/wx/gtk/platform.rkt")]))
+  (let ([gtk-lib
+         '(lib "mred/private/wx/gtk/platform.rkt")])
+    (case (system-type)
+      [(windows) (if (getenv "PLT_WIN_GTK")
+                     gtk-lib
+                     '(lib "mred/private/wx/win32/platform.rkt"))]
+      [(maxcosx) '(lib "mred/private/wx/cocoa/platform.rkt")]
+      [(unix) gtk-lib])))
 
 (define-values (button%
                 canvas%