libguestfs: remove xen as dependency

[tfmoraes]

Motivation for this change

Xen is not a dependency of Libguestfs, so this PR removes Xen from libguestfs dependencies. It also uses autoconf 2.64 instead of the last one in Nix, because it's not building with the last version.

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.

[tfmoraes]

nix-shell -p nixpkgs-review --run "nixpkgs-review wip"                                               
$ git -c fetch.prune=false fetch --force https://github.com/NixOS/nixpkgs master:refs/nixpkgs-review/0
$ git worktree add /home/thiago/.cache/nixpkgs-review/rev-70d194c818fea9bc77d50f13f431f45cbcda7602-dirty-2/nixpkgs 4b0a2ac72cac7116581ce883ce2f22de08e913cd
Preparing worktree (detached HEAD 4b0a2ac72ca)
HEAD is now at 4b0a2ac72ca Merge pull request #99559 from JamieMagee/nzbhydra2
$ nix-env -f /home/thiago/.cache/nixpkgs-review/rev-70d194c818fea9bc77d50f13f431f45cbcda7602-dirty-2/nixpkgs -qaP --xml --out-path --show-trace
Applying `nixpkgs` diff...
$ nix-env -f /home/thiago/.cache/nixpkgs-review/rev-70d194c818fea9bc77d50f13f431f45cbcda7602-dirty-2/nixpkgs -qaP --xml --out-path --show-trace --meta
6 packages updated:
libguestfs libguestfs python3.7-guestfs python3.8-guestfs python3.9-guestfs vagrant

$ nix --experimental-features nix-command build --no-link --keep-going --option build-use-sandbox relaxed -f /home/thiago/.cache/nixpkgs-review/rev-70d194c818fea9bc77d50f13f431f45cbcda7602-dirty-2/build.nix
6 packages built:
libguestfs libguestfs-with-appliance python37Packages.guestfs python38Packages.guestfs python39Packages.guestfs vagrant

[SuperSandro2000]

This is a semi-automatic executed nixpkgs-review which does not build all packages (e.g. lumo, tensorflow or pytorch)
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 108882 run on x86_64-linux 1

5 packages built:

• libguestfs
• python37Packages.guestfs
• python38Packages.guestfs
• python39Packages.guestfs
• vagrant

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

python37Packages.guestfs:

Zero tests run by pytest got detected: 'Ran 0 tests in 0.000s'
You have the following options to fix this:

• Tell pytest(CheckHook) where to find the tests included in the package
• Check if the GitHub Repo contains tests but they are not shipped with Pypi. If so please switch to fetchFromGitHub.
• If the Packages does not contain any tests add 'doCheck = false;'and apythonImportsCheck`.

python38Packages.guestfs:

Zero tests run by pytest got detected: 'Ran 0 tests in 0.000s'
You have the following options to fix this:

• Tell pytest(CheckHook) where to find the tests included in the package
• Check if the GitHub Repo contains tests but they are not shipped with Pypi. If so please switch to fetchFromGitHub.
• If the Packages does not contain any tests add 'doCheck = false;'and apythonImportsCheck`.

python39Packages.guestfs:

Zero tests run by pytest got detected: 'Ran 0 tests in 0.000s'
You have the following options to fix this:

• Tell pytest(CheckHook) where to find the tests included in the package
• Check if the GitHub Repo contains tests but they are not shipped with Pypi. If so please switch to fetchFromGitHub.
• If the Packages does not contain any tests add 'doCheck = false;'and apythonImportsCheck`.

[bryanasdev000]

Just tested, working fine, also Vagrants with libvirtd too.

[SuperSandro2000]

Result of nixpkgs-review pr 108882 run on x86_64-darwin 1

3 packages marked as broken and skipped:

• python37Packages.guestfs
• python38Packages.guestfs
• python39Packages.guestfs