[sudo-workers] missing --with-noexec in sudo-1.6.8/INSTALL

[Todd C. Miller]

Normally the value of --with-noexec is determined based on whether
or not libtool knows how to create a shared object on the OS in
question.  It is still worth documenting so that users can override
the default path though, so I will do that.

Please note that "noexec" is *not* enabled by default for commands.
The bits in configure just refer to whether or not it is possible
on the particular OS.  See the "PREVENTING SHELL ESCAPES" section
in the sudoers man page for details.

 - todd