It seems shotwell has the capability, you just have to compile it. I tried to configure with --define=ENABLE_FACES but the feature isn't showing up. I used playya git which included a recent fix for a compile faces error.
The Faces feature was #ifdef'd out of the source until Yorba could add a little more functionality to Shotwell to make it truly useful -- see http://redmine.yorba.org/issues/3934 and http://redmine.yorba.org/issues/1702. However, as we continued developing other features for Shotwell, the Faces code broke, so there's no way to build Shotwell with Faces support from trunk; see http://redmine.yorba.org/issues/4518
As you mentioned, a patch was made available at
It appears you can also use
Note that you can run Shotwell directly from the build directory. However, to make it available on your desktop and integrate with Nautilus and so forth, you'll need to do this:
To see the Faces button, open a photo (double-click on it). It's only available in the photo editor.
Warning: This fork has not been reviewed by Yorba yet. We can make no promises when the Faces feature will be fully integrated into Shotwell. There are other risks using the playya fork, including losing the ability to upgrade your database later. I recommend backing up your database before using it: http://redmine.yorba.org/projects/shotwell/wiki/ShotwellFAQ#How-can-I-back-up-my-Shotwell-library