Those who have the EAX SDK should indicate this on the command line by adding /DEAX_SDK_AVAILABLE to environment variable CL.
Trying to keep common project files and configurations between OU and Cyan for now, we'll see how that goes.
MarkD: My thought was for the long term was to put most of the differences in the project and solution configurations, so there would be less differences in the sources. EAX is a good example - I put the #define for EAX_SDK_AVAILABLE in the projects that used it with the thinking that the fans would create new projects that would not have EAX_SDK_AVAILABLE and would create and use a different configuration in the AllClient solution. Cyan would use the "Release" config and the fans use something like "Release-ou" to build with. But maybe there are just too many differences.