LICENSE* files not included in the SDist (via standard tooling)

[henryiii]

When building an SDist via pipx run build, flit doesn't include LICENSE* files, so when building the wheel also via pipx run build, there are no licenses files unless there is a license = {files = ...} key (and then only one file is allowed). However, when directly building the wheel, using pipx run build --wheel without going through an SDist first, then LICENSE* is included, see https://github.com/pypa/flit/blob/048c87c380ac41efc4b26222114e54f6581c64f6/flit_core/flit_core/wheel.py#L185.

#540 is slightly related. Noticed when trying to setup packaging on Flit in https://github.com/pypa/packaging/issues/340#issuecomment-1124289983 .

[bhrutledge]

Duplicate of #379?

[takluyver]

Yes, I think #379 covers this, thanks!