Hello Guix,

The 'glib' package gained SELinux support back in commit
6c237a2d7bfa3c7be02c069e5c24a2b401a51864.  We do not currently support
SELinux in Guix System, so I'm not sure if it is worth having it in
GLib.  Perhaps it can be useful on foreign distributions?

It does not add a lot to the GLib size (~3.8 MiB), but it is a
propagated dependency that can be easily avoided.

Thoughts?