* Update MimeSet rule to use the MIME DB the build system creates.
* Add CreateAppMimeDBEntries rule and call it from Link for targets that
might be applications that need to be registered with the MIME DB. For
the target the rule is invoked with it creates a directory into which
the entries for the types to be registered are written. The directory
is associated with the target via the HAIKU_MIME_DB_ENTRIES variable.
* AddFilesToContainer: If a target is added that has MIME DB entries,
also add those to the container.
* build_haiku_package: Call mimeset for the package contents.