[bug#40862] gnu: Add xarchiver.

[Mathieu Othacehe <m.othacehe@gmail.com>]

Hello Raghav,

Thanks for this patch. When running 'guix lint' on this patch, I have
the following warnings:

--8<---------------cut here---------------start------------->8---
/home/mathieu/guix-master/gnu/packages/compression.scm:87:5: xarchiver@0.5.4.14: the source file name should contain the package name
/home/mathieu/guix-master/gnu/packages/compression.scm:87:5: xarchiver@0.5.4.14: the source URI should not be an autogenerated tarball
fetching CVE database for 2020......
fetching CVE database for 2019...
fetching CVE database for 2018...
fetching CVE database for 2017...
/home/mathieu/guix-master/gnu/packages/compression.scm:85:13: xarchiver@0.5.4.14: can be upgraded to 0.5b2
--8<---------------cut here---------------end--------------->8---

>  
> +(define-public xarchiver
> +  (package
> +    (name "xarchiver")
> +    (version "0.5.4.14")
> +    (source
> +     (origin
> +       (method url-fetch)
> +       (uri
> +        (string-append "https://github.com/ib/" name "/archive/"
> +                       version ".tar.gz"))

You should use "git-fetch" method for github repositories (see linter
warning above).

> +       (list
> +        "--disable-plugin")))           ; Not required

Why is it not required?

> +    (synopsis "Graphical Front-end for Archive Operations")

No camel case notation.

> +    (description "Xarchiver is the ultimate solution for handling archives.  It
> +is a desktop-environment independent archiver front end.")

"Ultimate" is maybe exaggerated! Also you could elaborate a bit on the
functionalities of this tool.

Thanks,

Mathieu