This can break builds of existing SDL/WinRT apps. To fix, remove the reference to SDL_winrt_main.cpp, then add a reference to the renamed file, SDL_winrt_main_NonXAML.cpp. If you get a build error about a missing .winmd file, enable the /ZW compiler flag for that one file (at minimum).
1. remove references to SDL's project files from the Visual Studio Solution. To note, these project files have been renamed, and will show up in Visual Studio with the text, "load failed".
2. add the SDL project files back into the Visual Studio Solution
3. for each project that should link to SDL, add a reference to it. This can be done by right-clicking on it in Visual Studio, selecting "References...", clicking "Add New Reference", checking the box next to the SDL project, then closing each dialog by clicking OK.
SDL_mixer, SDL_ttf, and SDL_image for WinRT have been updated, and will be pushed to my Bitbucket repos with these changes having been made. If you do not pull in these changes, be sure to re-add to them the reference to the SDL project, as described above.