This commit adds a new service type to generate configuration file for the mpv
media player.
Originally I attempted to use Guix Records (via define-configuration) for
this, but ran into the bug #74748, so I had to switch to procedures instead.
The usage is (hopefully) sufficiently described in the documentation. When
the bug is resolved, I will update it to use define-configuration instead.
The full list of supported options is documented, however I decided to *not*
document types and purpose for each individual fields. While I had mostly
working prototype to extract the documentation from mpv, once I realized it
would be few 10k of lines added, I decided it is not worth it. It would bloat
the .texi file (by more than 50%), be hard to maintain and, in my opinion,
would not provide enough value to justify that. The current version seems
like sane middle ground.
* gnu/home/services/mpv.scm: New file.
* gnu/local.mk (GNU_SYSTEM_MODULES): Register it.
* doc/guix.texi (mpv Media Player): Document it.
Change-Id: I2deb44799a28047cb5d67da97dc6007a9df873af
