ffmpegthumbnailer: enable generation of thumbnailer file

[vs49688]

Motivation for this change

Makes ffmpegthumbnailer usable with desktop environments.

I've specifically used it to get video thumbnailing working on MATE (on 20.09).

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS linux)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.

[SuperSandro2000]

Result of nixpkgs-review pr 107632 run on x86_64-linux 1

4 packages built:

• ffmpegthumbnailer
• geeqie
• spaceFM
• xfce.tumbler

[vs49688]

Ping? I've done the requested changes.

[SuperSandro2000]

This is a semi-automatic executed nixpkgs-review. If you find some bugs or got suggestions for further things to search or run please reach out to SuperSandro2000 on IRC.

Result of nixpkgs-review pr 107632 run on x86_64-linux 1

4 packages built:

• ffmpegthumbnailer
• geeqie
• spaceFM
• xfce.tumbler

The following issues got detected with the above build packages.
Please fix at least the ones listed with your changed packages:

ffmpegthumbnailer.log:

gpl2 is a deprecated license, check if project uses gpl2Plus or gpl2Only and change meta.license accordingly.

Near pkgs/development/libraries/ffmpegthumbnailer/default.nix:31:5:

   |
31 |     license = licenses.gpl2;
   |     ^

See: https://github.com/jtojnar/nixpkgs-hammering/blob/master/explanations/unclear-gpl.md

xfce.tumbler.log:

gpl2 is a deprecated license, check if project uses gpl2Plus or gpl2Only and change meta.license accordingly.

Near lib/attrsets.nix:344:7:

    |
344 |       value = f name (catAttrs name sets);
    |       ^

See: https://github.com/jtojnar/nixpkgs-hammering/blob/master/explanations/unclear-gpl.md

[SuperSandro2000]

Also please squash the commits.

[vs49688]

Done

[SuperSandro2000]

This is a semi-automatic executed nixpkgs-review. If you find some bugs or got suggestions for further things to search or run please reach out to SuperSandro2000 on IRC.

Result of nixpkgs-review pr 107632 run on x86_64-linux 1

4 packages built:

• ffmpegthumbnailer
• geeqie
• spaceFM
• xfce.tumbler

The following issues got detected with the above build packages.
Please fix at least the ones listed with your changed packages:

xfce.tumbler.log:

gpl2 is a deprecated license, check if project uses gpl2Plus or gpl2Only and change meta.license accordingly.

Near lib/attrsets.nix:344:7:

    |
344 |       value = f name (catAttrs name sets);
    |       ^

See: https://github.com/jtojnar/nixpkgs-hammering/blob/master/explanations/unclear-gpl.md

[vs49688]

tumbler is a different package, it should be fixed in a different PR, or at the very least a different commit.

[vs49688]

Also where's that gpl2 coming from, it appears not to be set for xfce.tumbler:
In: pkgs/desktops/xfce/core/tumbler/default.nix:

  meta = {
    description = "A D-Bus thumbnailer service";
  };

EDIT: Right, so it's from pkgs/desktops/xfce/mkXfceDerivation.nix. Changing that is beyond the scope of this PR imo.

[SuperSandro2000]

Also where's that gpl2 coming from, it appears not to be set for xfce.tumbler:
In: pkgs/desktops/xfce/core/tumbler/default.nix:

  meta = {
    description = "A D-Bus thumbnailer service";
  };

EDIT: Right, so it's from pkgs/desktops/xfce/mkXfceDerivation.nix. Changing that is beyond the scope of this PR imo.

This is a semi-automatic executed nixpkgs-review.

Please fix at least the ones listed with your changed packages: