+ 2008/03/27 version 2008.01

Joshua Kronengold, mneme at io dot com, sent in a patch
to use IO::File instead of the $gensym hack.  Applied.

Carl Fürstenber, azatoth at gmail dot com and others 
requested that license terms be spelled out.  Done.

+ 2004/11/19

Bugfix in &unlock for if the lock file has been removed.

Bugfix by Vadim O. Ustiansky <ustiansk@sai.msu.ru>.

+ 2001/06/05

Added $av0debug variable to note locking attempts in $0

+ 2001/05/18

Added lock_rename to the EXPORT list.

+ 2000/09/25

Added tests to make sure 'nonblocking' works

+ 1999/12/17

Added the lock_rename() function.

+ 1999/06/22

SunOS systems seem to fail with EWOULDBLOCK on locked files.

+ 1999/06/21

It appears that on some systems (HP-UX) a blocking call to flock()
can fail with EACCES instead of EAGAIN.

+ 1999/06/15

Perl changes.  File::Flock must change to keep up.  A call to
lock() had to be changed to &lock().  Why?

+ 1998/12/01

More fixes for Solaris.  

Modified the unlock() function so that it can be called as a reference.

+ 1998/11/30

Fixed the object-style interface.  

Attempt to fix a double-unlock bug that makes the Linux port unhappy

+ 1998/11/26	

Chaged O_RDONLY to O_RDWR for all file opens because Solaris won't let
you get an exclusive lock on a read-only file.  Crazy!  Change suggested
by Lupe Christoph <lupe@alanya.m.isar.de>.  Thanks!

Rewrote the handling of the removal of files created just so that
they could be locked.  Also tried to make sure that now file descriptors
could get leaked.