Detailed revision comments:

r6312 | marko | 2009-12-16 10:10:36 +0200 (Wed, 16 Dec 2009) | 6 lines
branches/zip: fil_close(): Add #ifndef UNIV_HOTBACKUP around a debug
assertion on mutex.magic_n.  InnoDB Hot Backup is a single-threaded
program and does not contain mutexes.  This change allows InnoDB Hot
Backup to be compiled with UNIV_DEBUG.

Suggested by Michael Izioumtchenko.