added third buttonglyph from Tom Lisjac

git-svn-id: trunk@4371 -

lcl/include/buttonglyph.inc

@@ -91,6 +91,7 @@ begin
   case State of
     bsDisabled:  if NumGlyphs>1 then ImgID:=1;
     bsDown:      if NumGlyphs>2 then ImgID:=2;
+    bsExclusive: if NumGlyphs>3 then ImgID:=3;
   end;
 
   Result := Rect((ImgID*gWidth), 0, ((ImgID+1)*gWidth), gHeight);