I needed to get the authbind utility, available from:

  http://www.chiark.greenend.org.uk/ucgi/~ijackson/cvsweb/authbind/

up and running on a Mac OSX box (specifically, Mac OSX 10.7 Lion).  I made
a few changes to the source code; most of the changes are in the Makefile.

To install this authbind on your Mac OSX, simply do:

  # cd MacOSX-authbind
  # make
  # sudo make install

Then set up the authbind config files as one would normally.

Changes
--------
Here's the list of changes I made, and why:

 + PRELOAD_VAR defined to "DYLD_INSERT_LIBRARIES", rather than to "LD_PRELOAD"

 + Added setting of DYLD_FORCE_FLAT_NAMESPACE env var, as per dyld(1) man
   page recommendation.

 +  Added more logging to stderr of errors found in libauthbind, and the helper.

The original files are marked as .orig; this distribution also contains a
patches/macosx/ directory with the diffs, for easier inspection.  Note that
I did not make the Makefile intelligent enough to Do The Right Thing(tm) for
Linux platforms; it is currently specific to Mac OSX.