* gnu/packages/kodi.scm (libdvdnav/kodi): Update to 6.0.0-Leia-Alpha-1.
(libdvdread/kodi): Update to 6.0.0-Leia-Alpha-1.
(libdvdcss/kodi): Update to 1.4.1-Leia-Alpha-1.
(kodi): Update to 18.0_alpha-8.ec16dbc.
[version]: Use GIT-VERSION.
[source](file-name): Use GIT-FILE-NAME.
[arguments]: Adjust substitution.
[home-page]: Use HTTPS.