Allow unrar to overwrite files

[cookie99999]

On systems without the appropriate 7zip functionality, corrupt files will be created in the working directory, causing unrar to fail as its default behavior is to disallow overwriting files with the same names. Fixes #489

[darodi]

@cookie99999

What linux distribution are you using?
On ubuntu, I get this:

# unrar x -y -o+ -x__MACOSX -x.DS_Store -xthumbs.db -xThumbs.db test.rar
unrar: invalid option -- 'y'
Try `unrar --help' or `unrar --usage' for more information.

# unrar --help
Usage: unrar [OPTION...] ARCHIVE [FILE...] [DESTINATION]
Extract files from rar archives.

  -x, --extract              Extract files from archive (default)
  -t, --list                 List files in archive
  -f, --force                Overwrite files when extracting
      --extract-newer        Only extract newer files from the archive
      --extract-no-paths     Don't create directories while extracting
  -p, --password             Decrypt archive using a password
  -?, --help                 Give this help list
      --usage                Give a short usage message
  -V, --version              Print program version

We should maybe revert #370 instead

[cookie99999]

I am using Debian 11 (stable). Strangely enough I get the same output as you when trying to use unrar manually, but it works from within the program.
p7zip-rar works fine, so for Debian based systems you don't need unrar as a fallback, however it seems other distros might not have an equivalent package.

[darodi]

@cookie99999

I'm not sure this is needed. The recommended package for linux installation is flatpak and its 7z version manages rar files.
Could you give me an example of problem to test your PR?

On fedora, 7z gives an error (nothing is unrared) and then falls back to unrar.

[darodi]

• related to use unrar for fedora only #515

[cookie99999]

I described the problem in my comment on #489 . The unrar fallback is not necessary on Debian based systems, you just have to install p7zip-rar. I was running from source, not using flatpak.
A better solution than my PR would probably be to merge #515 instead, but if 7z fails, advise the user to check if p7zip-rar is installed.

[darodi]

thanks, I added your readme changes to #515