Motivation for this change

youtube-dl imports every extractor it has unless the youtube_dl/extractor/lazy_extractors.py module is built.

This updates nixpkgs' youtube-dl to build the module, improving startup time.

Testing on an Intel 4790K / NVMe drive:

before:

# time youtube-dl --help > /dev/null
youtube-dl --help > /dev/null  0.26s user 0.06s system 100% cpu 0.322 total

# strace youtube-dl 'https://www.youtube.com/watch?v=nJ9IdzcQMoc' 2>&1 | grep extractor/ | grep \.pyc | wc -l
789

after:

# time youtube-dl --help > /dev/null
youtube-dl --help > /dev/null  0.13s user 0.05s system 100% cpu 0.182 total

# strace youtube-dl 'https://www.youtube.com/watch?v=nJ9IdzcQMoc' 2>&1 | grep extractor/ | grep \.pyc | wc -l
6

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS)
• 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 nix-review --run "nix-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)
• Assured whether relevant documentation is up to date
• Fits CONTRIBUTING.md.