Observe that my test fails because the trackdown copy of the repo
doesn't use --set-scripts-executable.

$ darcs --version
1.0.9rc1 (release candidate 1)
$ grep executable ~/.darcs/defaults
ALL set-scripts-executable
$ darcs trackdown ./transmute
Tracking down command:
./transmute
/bin/sh: ./transmute: Permission denied
Trying without the patch:
Wed Sep 19 01:27:36 EST 2007  Trent W. Buck <twb@cyber.com.au>
  * Mimic sh -x.
/bin/sh: ./transmute: Permission denied
Trying without the patch:
Mon Aug 20 06:54:36 EST 2007  Trent W. Buck <trentbuck@gmail.com>
  * Care when a child fails.
/bin/sh: ./transmute: Permission denied
Trying without the patch:
Mon Aug 20 06:52:46 EST 2007  Trent W. Buck <trentbuck@gmail.com>
  * Define FORK-AND-WAIT.
/bin/sh: ./transmute: Permission denied
Trying without the patch:
Mon Aug 20 06:49:48 EST 2007  Trent W. Buck <trentbuck@gmail.com>
  * Define WHEN, UNLESS and ASSERT.
/bin/sh: ./transmute: Permission denied
Trying without the patch:
Mon Aug 20 05:53:04 EST 2007  Trent W. Buck <trentbuck@gmail.com>
  * Implement command-line interface.
  No argument parsing yet.
Noone passed the test!