I created WGI, a GUI lib written with C. WGI is open source. I issue the demo project of WGI 1.0.0. Here to download its source code: http://code.google.com/p/oic-wgi/downloads/list
What WGI? WGI is doing what MFC has done, to encapsulate API, BUT WGI uses OIOIC, instead of C++.
Look forward to various advices sincerely.