diff --git a/gfx/common/d3d12_common.h b/gfx/common/d3d12_common.h
index 9b0f1d894a..b8a994938a 100644
--- a/gfx/common/d3d12_common.h
+++ b/gfx/common/d3d12_common.h
@@ -25,6 +25,11 @@
 #endif
 
 #define CINTERFACE
+#ifdef __MINGW32__
+#ifndef __in_ecount_opt
+#define __in_ecount_opt(s)
+#endif
+#endif
 #include <d3d12.h>
 #include "dxgi_common.h"
 
diff --git a/gfx/include/dxsdk/d3d12sdklayers.h b/gfx/include/dxsdk/d3d12sdklayers.h
index 11a1566bee..841c3f7b2e 100644
--- a/gfx/include/dxsdk/d3d12sdklayers.h
+++ b/gfx/include/dxsdk/d3d12sdklayers.h
@@ -2239,8 +2239,6 @@ enum D3D12_MESSAGE_ID
         D3D12_MESSAGE_ID_D3D12_MESSAGES_END	= ( D3D12_MESSAGE_ID_VIDEO_PROCESS_FRAMES_INVALID_ARGUMENT + 1 ) 
     } 	D3D12_MESSAGE_ID;
 
-static_assert(D3D12_MESSAGE_ID_GPU_BASED_VALIDATION_UNSUPPORTED == 1000, "Publicly released SDK D3D12_MESSAGE_ID enum values must not be changed. New enum values must be added to the end of the list.");
-static_assert(D3D12_MESSAGE_ID_COPY_INVALIDLAYOUT == 1067, "Publicly released SDK D3D12_MESSAGE_ID enum values must not be changed. New enum values must be added to the end of the list.");
 typedef struct D3D12_MESSAGE
     {
     D3D12_MESSAGE_CATEGORY Category;