windows: Clean out things that should be using defined(SDL_PLATFORM_WINDOWS).

src/render/direct3d11/SDL_render_d3d11.c

@@ -787,16 +787,12 @@ done:
     return result;
 }
 
-#if defined(SDL_PLATFORM_WIN32) || defined(SDL_PLATFORM_WINGDK)
-
 static DXGI_MODE_ROTATION D3D11_GetCurrentRotation(void)
 {
     // FIXME
     return DXGI_MODE_ROTATION_IDENTITY;
 }
 
-#endif // defined(SDL_PLATFORM_WIN32) || defined(SDL_PLATFORM_WINGDK)
-
 static BOOL D3D11_IsDisplayRotated90Degrees(DXGI_MODE_ROTATION rotation)
 {
     switch (rotation) {

src/render/software/SDL_rotate.c

@@ -32,7 +32,7 @@ Andreas Schiffler -- aschiffler at ferzkopp dot net
 
 #ifdef SDL_VIDEO_RENDER_SW
 
-#if defined(SDL_PLATFORM_WIN32) || defined(SDL_PLATFORM_GDK)
+#if defined(SDL_PLATFORM_WINDOWS)
 #include "../../core/windows/SDL_windows.h"
 #endif