Fix Windows User Mode Build Breaks from VS v16.10 Update (microsoft#1646

)

Completing this as is so we can unblock some work.

src/inc/quic_platform.h

@@ -17,6 +17,8 @@ Supported Environments:
 
 #pragma once
 
+#include <stddef.h>
+
 #define IS_POWER_OF_TWO(x) (((x) != 0) && (((x) & ((x) - 1)) == 0))
 
 //

src/inc/quic_platform_winkernel.h

@@ -30,6 +30,7 @@
 #pragma warning(disable:26071)
 #pragma warning(disable:28118)
 #pragma warning(disable:28196)
+#pragma warning(disable:28251)
 #pragma warning(disable:28252)
 #pragma warning(disable:28253)
 #pragma warning(disable:28309)

src/inc/quic_platform_winuser.h

@@ -35,6 +35,7 @@
 
 #pragma warning(push) // Don't care about OACR warnings in publics
 #pragma warning(disable:26036)
+#pragma warning(disable:28251)
 #pragma warning(disable:28252)
 #pragma warning(disable:28253)
 #pragma warning(disable:5105) // The conformant preprocessor along with the newest SDK throws this warning for a macro.