d3d12.h, d3d12sdklayers.h: fix build against older mingw-w64 versions.

Fixes: https://github.com/libsdl-org/SDL/issues/10452 .

src/video/directx/d3d12.h

@@ -50,6 +50,13 @@
 #endif
 #endif
 
+#ifndef _In_opt_count_
+#define _In_opt_count_(x)
+#endif
+#ifndef _In_count_
+#define _In_count_(x)
+#endif
+
 /* Forward Declarations */ 
 
 #ifndef __ID3D12Object_FWD_DEFINED__
@@ -586,7 +593,9 @@ extern "C"{
 /* [local] */ 
 
 #include <winapifamily.h>
+#ifdef _MSC_VER
 #pragma region App Family
+#endif
 #if WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_APP | WINAPI_PARTITION_GAMES)
 #ifndef _D3D12_CONSTANTS
 #define _D3D12_CONSTANTS
@@ -34845,7 +34854,9 @@ EXTERN_C const IID IID_ID3D12GBVDiagnostics;
 /* [local] */ 
 
 #endif /* WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_APP | WINAPI_PARTITION_GAMES) */
+#ifdef _MSC_VER
 #pragma endregion
+#endif
 DEFINE_GUID(IID_ID3D12Object,0xc4fec28f,0x7966,0x4e95,0x9f,0x94,0xf4,0x31,0xcb,0x56,0xc3,0xb8);
 DEFINE_GUID(IID_ID3D12DeviceChild,0x905db94b,0xa00c,0x4140,0x9d,0xf5,0x2b,0x64,0xca,0x9e,0xa3,0x57);
 DEFINE_GUID(IID_ID3D12RootSignature,0xc54a6b66,0x72df,0x4ee8,0x8b,0xe5,0xa9,0x46,0xa1,0x42,0x92,0x14);

src/video/directx/d3d12sdklayers.h

@@ -206,7 +206,9 @@ extern "C"{
 /* [local] */ 
 
 #include <winapifamily.h>
+#ifdef _MSC_VER
 #pragma region App Family
+#endif
 #if WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_APP | WINAPI_PARTITION_GAMES)
 
 
@@ -4224,7 +4226,9 @@ EXTERN_C const IID IID_ID3D12InfoQueue1;
 /* [local] */ 
 
 #endif /* WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_APP | WINAPI_PARTITION_GAMES) */
+#ifdef _MSC_VER
 #pragma endregion
+#endif
 DEFINE_GUID(IID_ID3D12Debug,0x344488b7,0x6846,0x474b,0xb9,0x89,0xf0,0x27,0x44,0x82,0x45,0xe0);
 DEFINE_GUID(IID_ID3D12Debug1,0xaffaa4ca,0x63fe,0x4d8e,0xb8,0xad,0x15,0x90,0x00,0xaf,0x43,0x04);
 DEFINE_GUID(IID_ID3D12Debug2,0x93a665c4,0xa3b2,0x4e5d,0xb6,0x92,0xa2,0x6a,0xe1,0x4e,0x33,0x74);