GL was already participially disabled because X11 is disabled and lead to
the following error when building gst-plguins-good:
```
Did not find CMake 'cmake'
Found CMake: NO
Run-time dependency gstreamer-gl-prototypes-1.0 found: NO (tried pkgconfig and cmake)
Looking for a fallback subproject for the dependency gstreamer-gl-prototypes-1.0
meson.build:328:2: ERROR: Neither a subproject directory nor a gst-plugins-base.wrap file was found.
```
From SuperSandro2000's post-merge review of the PR adding this,
nixos/no-x-libs: add qtbase. Sandro added a comment about this after I had
already merged it; self'/super' previously masked the top level self/super.
Prior to this change, ffmpeg couldn't be built for an
environment.noXlibs system, because it would fail in:
ffmpeg → SDL2 → libdecor
ffmpeg certainly does not need support for SDL2 windowing on a noXlibs
system.
This fix is important because the minidlna NixOS test, which uses the
minimal profile (and therefore environment.noXlibs) and ffmpeg, can't
currently build.
The primary difference between the standard and minimal variants of
this package is that all the X libraries are removed from the minimal
variant.
I had to switch the order of the definitions in all-packages.nix to
avoid an infinite recursion after the overlay was applied.
the conversion procedure is simple:
- find all things that look like options, ie calls to either `mkOption`
or `lib.mkOption` that take an attrset. remember the attrset as the
option
- for all options, find a `description` attribute who's value is not a
call to `mdDoc` or `lib.mdDoc`
- textually convert the entire value of the attribute to MD with a few
simple regexes (the set from mdize-module.sh)
- if the change produced a change in the manual output, discard
- if the change kept the manual unchanged, add some text to the
description to make sure we've actually found an option. if the
manual changes this time, keep the converted description
this procedure converts 80% of nixos options to markdown. around 2000
options remain to be inspected, but most of those fail the "does not
change the manual output check": currently the MD conversion process
does not faithfully convert docbook tags like <code> and <package>, so
any option using such tags will not be converted at all.