Convert C_ASSERT to static_assert throughout codebase

[Copilot]

This PR converts all C_ASSERT usages to modern static_assert throughout the XDP for Windows codebase. Modern build toolchains support static_assert which provides better error messages and is part of the C11/C++11 standards.

Changes Made

• 72 total C_ASSERT instances converted across the entire codebase
• Used static_assert consistently for all files (C, C++, and headers)
• Added descriptive error messages to all static assertions for better debugging
• Removed conditional compilation blocks that previously distinguished between C and C++ usage

Files Updated

API Headers (25 instances)

• published/external/xdpapi.h - XDP API size assertions
• published/external/afxdp.h - AF_XDP structure size assertions
• All published/external/xdp/*.h headers - Extension and datapath structure assertions

Test Files (21 instances)

• test/functional/taef/tests.cpp - API version assertions
• test/functional/lib/tests.cpp - Buffer and connection structure assertions
• test/pktfuzz/pktfuzz.c - Frame and buffer layout assertions
• test/fakendis/polldpc.c - NDIS structure size assertions

Source Files (26 instances)

• src/xdplwf/ - LWF driver alignment and offset assertions
• src/xdp/xsk.c - XSK/XDP structure compatibility assertions
• src/rtl/inc/xdprefcount.h - Reference counting size assertions

Example Changes

Before:

C_ASSERT(sizeof(XDP_BUFFER) == 16);

After:

static_assert(sizeof(XDP_BUFFER) == 16, "XDP_BUFFER must be exactly 16 bytes");

The conversion maintains identical functionality while providing better error messages and using modern C/C++ standards consistently across the entire codebase.

Fixes #765.

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[mtfriesen]

@copilot always use static_assert and do not use _static_assert

[Copilot]

@copilot always use static_assert and do not use _static_assert

Updated all static assertions to use static_assert consistently throughout the codebase. Removed conditional compilation blocks and replaced all 72 instances of _Static_assert with static_assert as requested. See commit aa3d09b.