When dealing with in-memory lengths, the standard type "size_t" should
be used.  Missing one can be quite dangerous, because an attacker
could provoke an integer under-/overflow, which may provide an attack
vector.

git-svn-id: https://svn.musicpd.org/mpd/trunk@7205 09075e82-0dd4-0310-85a5-a0d7c8717e4f