Just went to compile PolicyKit 0.99, as it's a required dependency for libvirt.

However, it turns out that PolicyKit has a hard dependency upon gtk-doc:

  $ ./autogen.sh

  You must have gtk-doc installed to compile .
  Install the appropriate package for your distribution,
  or get the source tarball at http://ftp.gnome.org/pub/GNOME/sources/gtk-doc/
  $

Building of documentation should be an option, not a requirement.

As I'm attempting a build of PolicyKit on Mac OS X, this dependency now leads to this choice:

 a) Investigate packaging gtk-doc as well, as that's not already packaged
    on Mac OS X in Homebrew (one of the three main package systems for OSX)

    Unlikely to take this option, as gtk-doc will likely introduce its own
    dependencies.


 b) Investigate patching PolicyKit to not build docs and not depend on
    gtk-doc.

    Most likely, as that at least allows Policykit to be functional.  However,
    if the effort involved looks to be significant, then option c) will be
    used.


 c) Officially recommend people disable PolicyKit on their Virtualisation
    Servers if they need Mac OS X clients to connect, and document how to
    do it properly.


Best choice will be b), as that will preserve security and won't require updating the docs/instructions again if/when gtk-doc is made optional.