Provide useful default font paths on Mac OS
When compiling for Mac OS,
./configure automatically chooses
FC_DEFAULT_FONTS (for the built-in fallback configuration) unless it was overridden, which is not very useful as that directory doesn't normally exist, so unless there is some
fonts.conf installed applications using fontconfig won't find any fonts.
The conda package manager solves this by providing the default Mac OS font directories to
IMO it would be better to put these Mac OS system font directories into
FC_DEFAULT_FONTS such that even without a
fonts.conf installed (preferable for stand-alone applications), looking up system fonts will "just work". Since this is not package-manager specific, this should be done by fontconfig automatically. This requires that
FC_DEFAULT_FONTS can contain multiple directories.
I'll submit a MR that does this and automatically chooses said default system font directories on Mac OS, unless overridden on the
./configure command line.