I would like to mark the DesktopManager port as deprecated due to no upstream
support. The Portfile currently checks ${os.major} for an exact version. Should
specifying `deprecated.maximum_osmajor` be avoided due to being redundant?
Conversely, for ports that can be deprecated but are checking `${os.major}` as
a maximum version (rather than a minimum or exact), if they were to use
`deprecated.maximum_osmajor` should they then not be checking `${os.major}`?
Christopher A. Chavez
