TarArchiveOutputStream doesn't handle properly long link names, they are truncated silently in most cases.
- In GNU mode a @LongLink entry should be created similarly to long names but with the 'K' type (GNU_LONGLINK) instead of 'L' (GNU_LONGNAME)
- In POSIX mode a pax header with the linkpath keyword should be added. This is already implemented for links containing a non ASCII character.
- In the default ERROR mode no exception is thrown and the link is truncated.
The logic for adding a pax header on non ASCII characters should probably be reworked, as it seems possible to have pax headers mixed with GNU @LongLink entries. I'm not sure this is desirable.