implement default width for toolbar lables (from trunk r60199)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_2_9_0_BRANCH@60630 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/aui/auibar.cpp

@@ -554,7 +554,13 @@ wxSize wxAuiDefaultToolBarArt::GetLabelSize(
 
     // get item's width
     width = item.GetMinSize().GetWidth();
-
+    
+    if (width == -1)
+    {
+        // no width specified, measure the text ourselves
+        width = dc.GetTextExtent(item.GetLabel()).GetX();
+    }
+    
     return wxSize(width, height);
 }