If it encounters an inode whose owner does not have a pw entry, quot
allocates a 7-byte buffer (8 in practice, since that is the minimum
allocation size) and uses it to store the numeric uid preceded by a
hash character. This will overflow the allocated buffer if the UID
exceeds 6 decimal digits. Avoid this by using asprintf() instead.
While here, simplify the common case as well using strdup().
Reported by: Igor Gabriel Sousa e Souza
MFC after: 3 days