there are runtime environments like cygwin, which gives you the
source code level compability. But you have to compile the entire
source code targert as win32 binary.
http://www.cygwin.com/

but there are supported under some constraints.You need some
little change in you're code base.

A bit more explanation please

I install Cygwin then I (in Cygwin, hoping it has a GUI frontend) comply it (Cheese's source) as a Win32 binary? And thats it?

there is a include folder in the where cygwin installed. when you
search include files they should search on these files. So set up
the include search path to that include directory.

I honestly don't know how much GUI support as a font end from the
cygwin. and you can't use the GTK like things , try to strict to the
xlib , it is supported by cygwin. for other GUI frameworks you need
to download the libraries separately.

I actually contacted the author of Cheese and he said he be willing to do it but he doesnt understand enough of Windows to be able to port it himself so he needs some help...

Any takers?

you have to compile the entire
source code targert as win32 binary.
http://www.cygwin.com/