Fix build in the face of updates elsewhere (taglib)

Taglib's CMake support has changed without mind for backwards
compatibility, so old users were using variables that are
now unset. Switch to modern CMake instead.

While here:

• fix the WWW link, which led to a 500
• GH account HessiJames renamed dfaust; you'll note the SHA256 in the distinfo is not changed although the name of the file is.

PR: 247907