"make modules_install" with an "M=" file name ending in "/." breaks at
least rtl8812au-aircrack-ng-linux-module. In general, passing a more
human-generated-looking value seems prudent as these are more likely to
be tested upstream.
* guix/build/linux-module-build-system.scm (build, install): Call
CANONICALIZE-PATH on SOURCE-DIRECTORY instead of STRING-APPEND.
Reported by Maxim Cournoyer <maxim.cournoyer@gmail.com>.
as apteryx on #guix