Add build instructions for 32-bit Raspbian

[SeanTAllen]

Closes #3848

[SeanTAllen]

@kulibali is tune=native required for both of these? I know to get it to build it is only needed by configure, but I'm not sure if once you give to configure if it is carried over for future operations. Ditto arch etc all.

[ponylang-main]

Hi @SeanTAllen,

The changelog - added label was added to this pull request; all PRs with a changelog label need to have release notes included as part of the PR. If you haven't added release notes already, please do.

Release notes are added by creating a uniquely named file in the .release-notes directory. We suggest you call the file 3879.md to match the number of this pull request.

The basic format of the release notes (using markdown) should be:

## Title

End user description of changes, why it's important,
problems it solves etc.

If a breaking change, make sure to include 1 or more
examples what code would look like prior to this change
and how to update it to work after this change.

Thanks.