DXC won't compile now with MSVC build tools v14.51

[keptsecret]

Description
Latest MSVC update (v14.51) results in warnings being treated as errors when trying to compile DXC.
The following error is shown

2>\dxc\dxc\include\llvm\ADT\StringRef.h(579,10): warning C5285: cannot declare a specialization for 'std::is_nothrow_constructible': Specializing this standard library template is forbidden by N5014 [meta.rqmts]/4 [C:\Users\Nut\Nabla-origin\build\dynamic\3rdparty\dxc\build\lib\Transforms\Utils\LLVMTransformUtils.vcxproj]
2>    (compiling source file '../../../../../../../../../3rdparty/dxc/dxc/lib/Transforms/Utils/SimplifyIndVar.cpp')
2>        C:\Program Files\Microsoft Visual Studio\18\Community\VC\Tools\MSVC\14.51.36231\include\type_traits(1014,43):
2>        see declaration of 'std::is_nothrow_constructible'
2>        C:\Users\Nut\Nabla-origin\3rdparty\dxc\dxc\include\llvm\ADT\StringRef.h(579,10):
2>        to simplify migration, consider the temporary use of /Wv:18 flag with the version of the compiler with which you used to build without warnings

And it happens across various source files.

Steps to Reproduce
Update Visual Studio and build tools to the latest version (v14.51). Try to compile DXC.

Actual Behavior
It should compile

Environment

• DXC version 54afd2c
• Host Operating System Windows

[keptsecret]

Actually, I see a related PR that comes after the commit I'm on, though that one says Apple toolchain.
#8307

Gonna check if trunk works. Then I'll close this.

[jimblandy]

@keptsecret My bet: trunk won't work, because the preprocessor condition is specific to LLVM (that is, Apple):

#if !defined(_LIBCPP_VERSION)

I believe _LIBCPP_VERSION is specific to LLVM's libc++.