We are going to use freetype instead of the old custom TTF parser,
since the old parser has many annoying bugs when handling non-Latin
fonts and fixing it is not really worth the time.
On Windows, Freetype is built from a submodule.
On Linux and OS X, Freetype is provided together with the desktop,
though development files have to be installed separately.
After this change, SolveSpace does not contain nonfree assets.
Additionally, Perl is not required for the build.
Note that in the US, case law suggests that copyright does
not apply to bitmap fonts:
http://www.renpy.org/wiki/renpy/misc/Bitmap_Fonts_and_Copyright
Nevertheless, it was prudent to replace the asset with something
that is unambiguously free.
whitequark