xdgmime: Prevent infinite loops from badly-formed MIME registrations
Prevent recursion of _xdg_mime_cache_mime_type_subclass()
with the
same value of argument mime
for the subclasses of a MIME type.
This was observed in GLib as https://gitlab.gnome.org/GNOME/glib/-/issues/1875, and a backtrace of the infinite loop is here: https://gitlab.gnome.org/GNOME/glib/-/issues/1875#note_592829.
Signed-off-by: Philip Withnall withnall@endlessm.com
Helps: #32
Edited by Philip Withnall