diff --git a/widget/src/os2/nsGfxDefs.h b/widget/src/os2/nsGfxDefs.h
index d12df55a686..a0493b04505 100644
--- a/widget/src/os2/nsGfxDefs.h
+++ b/widget/src/os2/nsGfxDefs.h
@@ -29,6 +29,7 @@
 #define INCL_PM
 #define INCL_DOS
 #define INCL_DOSERRORS
+#define INCL_DEV
 #include <os2.h>
 #include "prlog.h"