Converting Unix Opengl Programs to Windows

I have a graphics post processor written in C which has been developed on a Workstation. It uses the opengl facilities. Whenever I try to compile the program it comes out with lots of syntax errors an example of which is

error C2054: expected ‘(’ to follow ‘WINGDIAPI’

It is probably a trivial problem, but can anyone enlighten me on the syntax differences between unix based opengl and windows based

you will need to include <windows.h> before any opengl include files.

Thank you for the tip

Originally posted by dallas:
you will need to include <windows.h> before any opengl include files.