To fill in some gaps, I've had to make some assumptions:

* trivial changes (such as checking for an additional function or
  header file in libglnx.m4) are assumed to not be copyrightable
* Will Thompson and Matthew Leeds are assumed to be contributing on
  behalf of Endless Mobile Inc.
* files with no explicit licensing information are assumed to be
  under the license found in COPYING

Reference: https://reuse.software/


Signed-off-by: Simon McVittie <smcv@debian.org>