diff --git a/gfx/src/os2/nsGfxDefs.h b/gfx/src/os2/nsGfxDefs.h
index d969b8461c73..1e6f7a01512e 100644
--- a/gfx/src/os2/nsGfxDefs.h
+++ b/gfx/src/os2/nsGfxDefs.h
@@ -28,6 +28,7 @@
 
 #define INCL_PM
 #define INCL_DOS
+#define INCL_DOSERRORS
 #include <os2.h>
 
 #include <uconv.h> // XXX hack XXX