trying to open files rather than giving up when it encounters an
error. ENOENT errors are not reported.
As a result, files that are moved away then recreated are not at
risk of being 'lost' to tail. Files that are recreated and
temporarily have unreadable permissions will be shown when they
are fixed.
This behaviour is consistent with the GNU version of tail but
without the verbiage that goes with the GNU version.
This change also fixes error messages accompanying -f and -F.
They no longer report problems with (null)!
MFC after: 3 weeks
long -> off_t
strtol -> strtoll
fseek -> fseeko
NOTE: that fseek not works for >long offsets files per POSIX:
[EOVERFLOW] For fseek( ), the resulting file offset would be a value which
cannot be represented correctly in an object of type long.
stat() the file being followed and do a close/reopen if the file has been
renamed and/or rotated. This is damn useful for leaving running on files
in /var/log when newsyslog(8) rotates them.
