getting fc-list to see gsfonts

[Mark Polesky]

So, after Julien's patch

  https://codereview.appspot.com/13390043

I finally get a proper error at the configure stage:

  ERROR: Please install required programs:  International
  New Century Schoolbook fonts (make sure the fc-list
  utility can see them, or use --with-ncsb-dir)

  See INSTALL.txt for more information on how to build
  LilyPond

After a lot of searching, I realized that all I needed was 

  ../configure --with-ncsb-dir=/usr/share/fonts/type1/gsfonts/

and now my fonts work (finally!).

But now I'm curious, how do I get fc-list to "see" the fonts
in the gsfonts directory?

Thanks.
- Mark