Some of GLib's unit tests are under an apparently GLib-specific
permissive license, vaguely similar to the BSD/MIT family but with the
GPL's lack-of-warranty wording. This is not on SPDX's list of
well-known licenses, so we need to use a custom license name prefixed
with LicenseRef if we want to represent this in SPDX/REUSE syntax.
Most of the newer tests seem to be licensed under LGPL-2.1-or-later
instead.
Signed-off-by: Simon McVittie <smcv@collabora.com>
