In Thomas Morley's report
http://lists.gnu.org/archive/html/bug-lilypond/2015-09/msg00007.html
seems to have two problems.
This issue is for fontconfig conf file is missing in LilyPond official web site's 2.19.26 binaries.
Another issue is Issue 4591.
I've made GUB's patch and updated pull request.
https://github.com/gperciva/gub/pull/20
This patch will fix this problem at 2.19.27.
GUB's pull request has been merged.
https://github.com/gperciva/gub/pull/20
LilyPond website's official binary 2.19.27 contains fontconfig conf files.