Regarding zlib and wxWidgets

Yep, that's exactly what I did.

Code:

<IncludePath>..\wxWidgets\src\zlib;

Code:

#include <zlib.h>

This satisfies Visual Studio and Travis, but Appveyor still fails on that include line.

EDIT: For the sake of completeness, I can quickly say what solved this issue.

I needed to include ZLIB_INCLUDE_DIR in the CMakeLists.txt file in rpcs3/rpcs3, and then I added the wxWidgets/src/zlib directory to the default props file for rpcs3. This satisfied both Appveyor and Visual Studio.