Glyphicons are not displayed in HTML exported files

Steps to reproduce

1. Export the main page to HTML. You get a Zip File.
2. Extract the zip file.
3. Open the HTML with your browser
4. The icons of the top menu are broken (but not the icons of the app bar, see screenshot).
5. Open skins/flamingo/style.css
   You will see (first line):

   @font-face{font-family:'Glyphicons Halflings';src:url('webjars/META-INF/resources/webjars/bootstrap/3.2.0/fonts/glyphicons-halflings-regular.eot')}
   

   The URL for glyphicons is:

   webjars/META-INF/resources/webjars/bootstrap/3.2.0/fonts/glyphicons-halflings-regular.eot
   

   but it should be:

   ../../webjars/META-INF/resources/webjars/bootstrap/3.2.0/fonts/glyphicons-halflings-regular.eot
   

Actually, if you look at ssx/IconThemes/FontAwesome/ssx.css, you have:

@font-face {
  font-family: 'FontAwesome';
  src: url('../../../webjars/META-INF/resources/webjars/font-awesome/4.2.0/fonts/fontawesome-webfont.eot');

So the relative URL is correctly generated on a SSX, but not on the skin css. Because of LESS? I don't know.