Comment 5 for bug 1441998

thanks for the info. Unfortunately the fontconfig library is an external library not maintained by Inkscape. You may get more info at:
http://www.freedesktop.org/wiki/Software/fontconfig/
there is also a mailing list at:
http://lists.freedesktop.org/mailman/listinfo/fontconfig
it might be worthwhile to post a question there to see if you get a response.