Visual Studio 2026 Windows build with ARM64EC warning _umul128 not available

the guard code for a Windows ARM64EC should be using _M_ARM64EC to know if the build is for arm64ec build. I don't believe _ARM64EC_ is defined by the compiler

include\rapidjson\internal\biginteger.h(23): warning C4163: '_umul128': not available as an intrinsic function include\rapidjson\internal\diyfp.h(29): warning C4163: '_umul128': not available as an intrinsic function

#if defined(_MSC_VER) && !defined(__INTEL_COMPILER) && defined(_M_AMD64) #include <intrin.h> // for _umul128 #if !defined(_ARM64EC_) #pragma intrinsic(_umul128) #else #pragma comment(lib,"softintrin") #endif #endif