various d_bg debug cleanup / d_menu_window_HIO debug (#3132)

* various d_bg debug cleanup

* matching forward decl for compiler compatibility

* fix build

src/d/d_bg_s_poly_pass_chk.cpp

@@ -84,7 +84,10 @@ bool dBgS_PolyPassChk::ChkNoHorse() {
         return true;
     }
 
-    return !ChkHorse();
+    if (!ChkHorse())
+        return true;
+
+    return false;
 }
 
 void dBgS_PolyPassChk::SetStatue() {