Oops, fix that fix. TranslateKey can return <0 and it needs to be

dealt with. I don't recall being told that; I should comment it at
some stage.

[originally from svn r1234]

window.c

@@ -1864,7 +1864,7 @@ static LRESULT CALLBACK WndProc(HWND hwnd, UINT message,
 		if (len == -1)
 		    return DefWindowProc(hwnd, message, wParam, lParam);
 
-		if (len > 0) {
+		if (len != 0) {
 		    /*
 		     * We need not bother about stdin backlogs
 		     * here, because in GUI PuTTY we can't do