Sync syslogd with -current, except the -o option. Includes:

1.128 Terminate program names if we hit a '/'.
1.127 Log file name may be prefixed by a '-' if it shouldn't be synced.
1.126 Be more careful about using using the file descriptor f_file.
1.125 String fixes (inspired by OpenBSD).
1.124 Warn about paths that are too long (OpenBSD).
1.123 Fix some not-in-practice bugs to do with log levels.
1.122 Update some comments.
1.121 Warns fixes.