Do not download source archives
Please please do not do this!

I just attempted to build choosenim on my system (which depends on nimarchive) which downloads https://sourceware.org/pub/bzip2/bzip2-1.0.8.tar.gz. As of time of writing this URL gives a 403 error... this is the error I got: https://gist.github.com/dom96/8e96ea883a32ab9ff00f3fb0cf476828 and indeed:

```
~/.cache/nim/nimterop/nimarchive/bzip2 » cat bzip2-1.0.8.tar.gz 
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
<html><head>
<title>403 Forbidden</title>
</head><body>
<h1>Forbidden</h1>
<p>You don't have permission to access /pub/bzip2/bzip2-1.0.8.tar.gz
on this server.<br />
</p>
</body></html>
```

Downloading archives in general during build times is flaky. The user has no control over the download and may not want the internet to be accessed at all. I think the solution here is to use git submodules instead and I am tempted to somehow disallow any package the ability to download things from the internet.