Busybox wget support

[fredrikfoss]

Hi, this pr adds support for Busybox's implementation of wget, which comes
default on Alpine Linux among other distros. Busyboxs wget only support POST,
but as far as I could tell wget won't be called with other methods here. This
should also close #1601. Let me know what you think.

Busybox wget documentation reference:

BusyBox v1.37.0 (2024-11-13 17:39:29 UTC) multi-call binary.

Usage: wget [-cqS] [--spider] [-O FILE] [-o LOGFILE] [--header STR]
        [--post-data STR | --post-file FILE] [-Y on/off]
        [-P DIR] [-U AGENT] [-T SEC] URL...

Retrieve files via HTTP or FTP

        --spider        Only check URL existence: $? is 0 if exists
        --header STR    Add STR (of form 'header: value') to headers
        --post-data STR Send STR using POST method
        --post-file FILE        Send FILE using POST method
        -c              Continue retrieval of aborted transfer
        -q              Quiet
        -P DIR          Save to DIR (default .)
        -S              Show server response
        -T SEC          Network read timeout is SEC seconds
        -O FILE         Save to FILE ('-' for stdout)
        -o LOGFILE      Log messages to FILE
        -U STR          Use STR for User-Agent header
        -Y on/off       Use proxy

[fredrikfoss]

On second thought, this really is just a quick workaround and should be done more thoroughly, if this is wanted. Initially, I was made aware of this issue simply because downloading packages didn't work when the wget binary was provided by Busybox, even though curl was available on the system and wget is marked as relaxed. Busybox wget does not support a --version argument, and returns false when given one, something relaxed doesn't seem to cover.

But wget isn't the only case. There is also gzip, unzip and tar (not tar though, the Busybox implementation actually supports --version ¯_(ツ)_/¯). There exists multiple implementations of some of these, not just by Busybox. I think a better approach might be to not check their versions or return values, and just assume they will work as indended if found in PATH. Then feed them options and flags that are common and found to work with most implementations. I can't remember seeing any actual complex or uncommon option or flag used with any of the coreutils in the source. This PR only changed a few flags to also work with Busybox wget.

Changing to draft for now. You can close it if you want, but I'm interested in hearing your or other' thoughts.