XML tools interpret “fonts.dtd” as a relative path.
Unfortunately, that can not work now that the configuration is spread over
multiple system-dependant directories, without a common relative path to this
file. And, an absolute path can not be defined in a system-independant way.
System independance is a requirement to share config files between systems.
Therefore, replace the broken relative path by a formal URN, that will work the
same way on all systems, without network access.
This makes the DTD registerable with commands like:
$ xmlcatalog --noout --add system \
"urn:fontconfig:fonts.dtd" \
"file:///usr/share/xml/fontconfig/fonts.dtd" \
/etc/xml/catalog
That enables easy config file checking:
$ xmllint --loaddtd ${config_file} >/dev/null
Trying to address what these configuration files really do.
This change allows to see the short description that mention
the purpose of the content in the config file and obtain
them through API.
This change also encourage one who want to make some UI for
the user-specific configuration management. it is the main
purpose of this change for me though.
Aside from that, I've also made programs translatable. so
we see more dependencies on the build time for gettext,
and itstool to generate PO from xml.
Allows reading configuration files, fonts and cache files from
the directories where the XDG Base Directory Specification defines.
the old directories are still in the configuration files for
the backward compatibility.