Qt6 Beta4 fails to compile with Clang - SIMD issues

[3/6697] Building CXX object qtbase/src/corelib/CMakeFiles/Core.dir/Debug/global/qsimd.cpp.obj
FAILED: qtbase/src/corelib/CMakeFiles/Core.dir/Debug/global/qsimd.cpp.obj
C:\PROGRA~1\LLVM\bin\CLANG_~1.EXE -DCore_EXPORTS -DPCRE2_CODE_UNIT_WIDTH=16 -DPCRE2_STATIC -DQT_ASCII_CAST_WARNINGS -DQT_BUILDING_QT -DQT_BUILD_CORE_LIB -DQT_CORE_QOBJECT_LIB -DQT_DEPRECATED_WARNINGS -DQT_DEPRECATED_WARNINGS_SINCE=0x060000 -DQT_DISABLE_DEPRECATED_BEFORE=0x040800 -DQT_MOC_COMPAT -DQT_NO_FOREACH -DQT_NO_USING_NAMESPACE -DQT_USE_QSTRINGBUILDER -DUNICODE -DWIN32 -DWIN64 -D_ENABLE_EXTENDED_ALIGNED_STORAGE -D_UNICODE -D_USE_MATH_DEFINES -D_WIN64 -DCMAKE_INTDIR=\"Debug\" -Iqtbase/src/corelib/Core_autogen/include_Debug -Iqtbase/include -Iqtbase/include/QtCore -Iqtbase/src/corelib -Iqtbase/src/corelib/global -Iqtbase/src/corelib/../3rdparty/tinycbor/src -Iqtbase/include/QtCore/6.0.0 -Iqtbase/include/QtCore/6.0.0/QtCore -Iqtbase/src/corelib/../3rdparty/double-conversion/.. -Iqtbase/src/corelib/../3rdparty/double-conversion/include -Iqtbase/src/corelib/.rcc -Iqtbase/mkspecs/win32-clang-msvc -Iqtbase/src/3rdparty/pcre2/src -isystem C:/Strawberry/c/include -g -Xclang -gcodeview -D_DEBUG -D_DLL -D_MT -Xclang --dependent-lib=msvcrtd -fvisibility-inlines-hidden -Wall -Wextra -Wno-ignored-attributes -std=c++17 -Xclang -include-pch -Xclang D:/Dev/Github/Qt6/qtbase/src/corelib/CMakeFiles/Core.dir/Debug/cmake_pch.hxx.pch -Xclang -include -Xclang D:/Dev/Github/Qt6/qtbase/src/corelib/CMakeFiles/Core.dir/Debug/cmake_pch.hxx -MD -MT qtbase/src/corelib/CMakeFiles/Core.dir/Debug/global/qsimd.cpp.obj -MF qtbase\src\corelib\CMakeFiles\Core.dir\Debug\global\qsimd.cpp.obj.d -o qtbase/src/corelib/CMakeFiles/Core.dir/Debug/global/qsimd.cpp.obj -c qtbase/src/corelib/global/qsimd.cpp
qtbase/src/corelib/global/qsimd.cpp:660:44: error: use of undeclared identifier '_rdrand64_step'
using randuint = ExtractParameter<decltype(_rdrandXX_step)>::Type;
 ^
qtbase/src/corelib/global/qsimd.cpp:647:28: note: expanded from macro '_rdrandXX_step'
# define _rdrandXX_step _rdrand64_step
 ^
qtbase/src/corelib/global/qsimd.cpp:671:25: error: use of undeclared identifier 'randuint'
 while (ptr + sizeof(randuint) / sizeof(*ptr) <= end) {
 ^
qtbase/src/corelib/global/qsimd.cpp:672:45: error: unknown type name 'randuint'
 if (_rdseedXX_step(reinterpret_cast<randuint *>(ptr)) == 0)
 ^
qtbase/src/corelib/global/qsimd.cpp:672:13: error: use of undeclared identifier '_rdseed64_step'
 if (_rdseedXX_step(reinterpret_cast<randuint *>(ptr)) == 0)
 ^
qtbase/src/corelib/global/qsimd.cpp:648:28: note: expanded from macro '_rdseedXX_step'
# define _rdseedXX_step _rdseed64_step
 ^
qtbase/src/corelib/global/qsimd.cpp:674:23: error: use of undeclared identifier 'randuint'
 ptr += sizeof(randuint) / sizeof(*ptr);
 ^
qtbase/src/corelib/global/qsimd.cpp:677:32: error: use of undeclared identifier 'randuint'
 if (sizeof(*ptr) != sizeof(randuint) && ptr != end) {
 ^
qtbase/src/corelib/global/qsimd.cpp:678:13: error: use of undeclared identifier '_rdseed32_step'
 if (_rdseed32_step(ptr) == 0)
 ^
qtbase/src/corelib/global/qsimd.cpp:696:25: error: use of undeclared identifier 'randuint'
 while (ptr + sizeof(randuint)/sizeof(*ptr) <= end) {
 ^
qtbase/src/corelib/global/qsimd.cpp:697:45: error: unknown type name 'randuint'
 if (_rdrandXX_step(reinterpret_cast<randuint *>(ptr)))
 ^
qtbase/src/corelib/global/qsimd.cpp:697:13: error: use of undeclared identifier '_rdrand64_step'
 if (_rdrandXX_step(reinterpret_cast<randuint *>(ptr)))
 ^
qtbase/src/corelib/global/qsimd.cpp:647:28: note: expanded from macro '_rdrandXX_step'
# define _rdrandXX_step _rdrand64_step
 ^
qtbase/src/corelib/global/qsimd.cpp:698:27: error: use of undeclared identifier 'randuint'
 ptr += sizeof(randuint)/sizeof(*ptr);
 ^
qtbase/src/corelib/global/qsimd.cpp:703:35: error: use of undeclared identifier 'randuint'
 while (sizeof(*ptr) != sizeof(randuint) && ptr != end) {
 ^
qtbase/src/corelib/global/qsimd.cpp:704:19: error: use of undeclared identifier '_rdrand32_step'
 bool ok = _rdrand32_step(ptr);
 ^
13 errors generated.
[28/6697] Building CXX object qtbase/src/corelib/CMakeFiles/Core.dir/Debug/kernel/qmetatype.cpp.obj
ninja: build stopped: subcommand failed.

#if !(defined(_MSC_VER) || defined(__SCE__)) || __has_feature(modules) || \
 defined(__RDRND__)
static __inline__ int __attribute__((__always_inline__, __nodebug__, __target__("rdrnd")))
_rdrand16_step(unsigned short *__p)
{
 return __builtin_ia32_rdrand16_step(__p);
}
static __inline__ int __attribute__((__always_inline__, __nodebug__, __target__("rdrnd")))
_rdrand32_step(unsigned int *__p)
{
 return __builtin_ia32_rdrand32_step(__p);
}
#ifdef __x86_64__
static __inline__ int __attribute__((__always_inline__, __nodebug__, __target__("rdrnd")))
_rdrand64_step(unsigned long long *__p)
{
 return __builtin_ia32_rdrand64_step(__p);
}
#endif
#endif /* __RDRND__ */