Well you have a couple of options.
GtkHTML
HTML rendering/printing/editing engine
http://ftp.gnome.org/pub/GNOME/sources/gtkhtml/3.15/
GtkMozEmbeded
Supports everything that Mozilla or Firefox does.
http://www.mozilla.org/unix/gtk-embedding.html
Let use know if you figure out how to actually build it.
Gtk+ Webcore
Supports everything KHTML does or will support.
The following standards are supported by the KHTML engine:
* HTML 4.01
* CSS 1
* CSS 2.1 (screen and paged media)
* CSS 3 Selectors
* CSS 3 Other (multiple backgrounds, box-sizing and text-shadow)
* PNG, MNG, JPEG, GIF graphic formats
* DOM 1, 2 and partially 3
* ECMA-262/JavaScript 1.5
* Partial Scalable Vector Graphics support
http://gtk-webcore.sourceforge.net/index.html
WebkitGdk "Gtk+ Webcore Fork"
Same as Gtk+ Webcore but may be more stable.
http://trac.webkit.org/projects/webkit/wiki/BuildingGdk
Or you could build your own.
Start by building an html parser and then use cairo
to render the pages that your html parser parses.
Here is a tutorial on building gtk+/cairo widgets.
Part 1
http://www.gnomejournal.org/article/34/ ... -and-gtk28
Part 2
http://www.gnomejournal.org/article/36/ ... k28-part-2
Hope that helps