cmake-macros: Allow for non-intltool build
Historically, gettext can't handle xml and desktop file natively, thus, intltool was invented to fill in this hole. Those file formats now can be handled natively by gettext 0.19.8 or later.
KDE's .provider and .service files marked with underscore prefix
in order to work with intltool for this specific purpose.
Unlike GNOME, KDE only has interest on extracting messages from those
files, KDE doesn't merge them back into one big file.
Let's drop those requirements on intltool when users asked (read,
users converted their files to native gettext format). Should we
take GNOME's road to merge those messages into one big file, we could
introduce msgfmt requirement later on.
Edited by Danh Doan