[clang] [clang] Add /Zc:__STDC__ flag to clang-cl (PR #68690)

[Aaron Ballman via cfe-commits]

================
@@ -7922,6 +7926,10 @@ void Clang::AddClangCLArgs(const ArgList &Args, types::ID InputType,
    CmdArgs.push_back("-fno-wchar");
  }
 
+ if (Args.hasArg(options::OPT_fms_define_stdc)) {
+   CmdArgs.push_back("-fms-define-stdc");
+ }
----------------
AaronBallman wrote:

```suggestion
 if (Args.hasArg(options::OPT_fms_define_stdc))
   CmdArgs.push_back("-fms-define-stdc");
```

https://github.com/llvm/llvm-project/pull/68690