__WINESRC__ has to go

We currently employ two methods for giving Wine-imported source the additional header definitions they need:

1) Using '#ifdef _WINESRC_' blocks in our PSDK headers and supplying this #define to every Wine module.

2) Creating a header with the same name as the PSDK one in include/reactos/wine, adding the definitions there and an '#include <psdk/headername.h>' at the end.

I consider the second method way cleaner, because it properly separates Wine-specific stuff from our meant-to-be-compatible PSDK headers. It also allows us to add include/reactos/wine for Wine modules only and remove this include directory for any other modules to keep things consistent.
A simple CMake function like set_wine_module() could also centralize this addition of the include directory.