gdi32: Add support for the null pen.

dlls/gdi32/dibdrv/objects.c

@@ -819,6 +819,11 @@ static BOOL dashed_pen_line(dibdrv_physdev *pdev, POINT *start, POINT *end)
     return TRUE;
 }
 
+static BOOL null_pen_line(dibdrv_physdev *pdev, POINT *start, POINT *end)
+{
+    return TRUE;
+}
+
 static const dash_pattern dash_patterns[5] =
 {
     {0, {0}, 0},                  /* PS_SOLID - a pseudo-pattern used to initialise unpatterned pens. */
@@ -892,6 +897,11 @@ HPEN CDECL dibdrv_SelectPen( PHYSDEV dev, HPEN hpen )
         pdev->defer &= ~DEFER_PEN;
         break;
 
+    case PS_NULL:
+        pdev->pen_line = null_pen_line;
+        pdev->defer &= ~DEFER_PEN;
+        break;
+
     default:
         break;
     }