pango-engine.h hides definitions

[Kyle Cavin <kyle cavin gmail com>]

Hi, I'm looking for info about using PangoEngines for specifying word
breaks using in GtkTextBuffer. When I try to use the pango-engine API,
I'm getting a bunch of implicit declaration errors. If I define
PANGO_ENABLE_ENGINE, I get link errors. I'm on a gentoo system if that
helps. I'm working on a text editor, so I'd like whatever I produce to 
work without crazy dependencies. Am I on the wrong track? Thanks.