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

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<!--LLVM CODE FORMAT COMMENT: {clang-format}-->

:warning: C/C++ code formatter, clang-format found issues in your code. :warning:

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``````````bash
git-clang-format --diff b4343aba9fa12ddb397e08208ec37fcf0fb93864 49681eace80c60d22e4d9ced4fabe2872f716bab -- clang/lib/Driver/ToolChains/Clang.cpp clang/lib/Frontend/InitPreprocessor.cpp clang/test/Driver/cl-zc.cpp
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View the diff from clang-format here.
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``````````diff
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index b8f3ff6cd4c9..2834786ba17d 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -6751,7 +6751,6 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
       CmdArgs.push_back("-fms-define-stdc");
   }
 
-
   if (Triple.isWindowsMSVCEnvironment() && !D.IsCLMode() &&
       Args.hasArg(options::OPT_fms_runtime_lib_EQ))
     ProcessVSRuntimeLibrary(Args, CmdArgs);
diff --git a/clang/lib/Frontend/InitPreprocessor.cpp b/clang/lib/Frontend/InitPreprocessor.cpp
index 46399f613257..e7ce08a8766d 100644
--- a/clang/lib/Frontend/InitPreprocessor.cpp
+++ b/clang/lib/Frontend/InitPreprocessor.cpp
@@ -423,7 +423,8 @@ static void InitializeStandardPredefinedMacros(const TargetInfo &TI,
   //      [C++] Whether __STDC__ is predefined and if so, what its value is,
   //      are implementation-defined.
   // (Removed in C++20.)
-  if ((!LangOpts.MSVCCompat || LangOpts.MSVCEnableStdcMacro) && !LangOpts.TraditionalCPP)
+  if ((!LangOpts.MSVCCompat || LangOpts.MSVCEnableStdcMacro) &&
+      !LangOpts.TraditionalCPP)
     Builder.defineMacro("__STDC__");
   //   -- __STDC_HOSTED__
   //      The integer literal 1 if the implementation is a hosted

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