webkit-gtk requires libc++ -- MacOS 10.9 or XCode 5?

[Richard Cobbe]

MacPorts 2.2.1, MacOS 10.8.5, XCode 4.6.3.

I tried to do a "port selfupdate; port upgrade outdated" this morning, and
it failed when attempting to install webkit-gtk:

    Error: webkit-gtk is not supported for this installation of MacPorts.
    It requires libc++ be selected as your C++ runtime.  Please use
    webkit-gtk-2.0 instead

I'm only using webkit-gtk as a dependency for gnucash, which doesn't appear
to like webkit-gtk-2.0.  Based on <http://trac.macports.org/ticket/41560>,
it looks like I'm out of luck on this package until I upgrade to Mavericks.
Is that correct?  (I'm finding the comments on that bug to be a little hard
to interpret.)  Or is it an XCode 4 vs. XCode 5 issue?

Thanks,

Richard