Fix vsync-off support for direct3d11

include/build_config/SDL_build_config.h.cmake

@@ -223,6 +223,7 @@
 #cmakedefine HAVE_WINDOWS_GAMING_INPUT_H 1
 #cmakedefine HAVE_GAMEINPUT_H 1
 #cmakedefine HAVE_DXGI_H 1
+#cmakedefine HAVE_DXGI1_5_H 1
 #cmakedefine HAVE_DXGI1_6_H 1
 
 #cmakedefine HAVE_MMDEVICEAPI_H 1

include/build_config/SDL_build_config_windows.h

@@ -85,6 +85,7 @@ typedef unsigned int uintptr_t;
 #define HAVE_DXGI_H 1
 #define HAVE_XINPUT_H 1
 #if defined(_WIN32_MAXVER) && _WIN32_MAXVER >= 0x0A00  /* Windows 10 SDK */
+#define HAVE_DXGI1_5_H 1
 #define HAVE_DXGI1_6_H 1
 #define HAVE_WINDOWS_GAMING_INPUT_H 1
 #endif

include/build_config/SDL_build_config_wingdk.h

@@ -37,6 +37,7 @@
 #define HAVE_DSOUND_H 1
 /* No SDK version checks needed for these because the SDK has to be new. */
 #define HAVE_DXGI_H 1
+#define HAVE_DXGI1_5_H 1
 #define HAVE_DXGI1_6_H 1
 #define HAVE_XINPUT_H 1
 #define HAVE_WINDOWS_GAMING_INPUT_H 1