[clang] [clang] Support --sysroot= for ${arch}-windows-msvc targets (PR #96417)

[Petr Hosek via cfe-commits]

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@@ -98,20 +98,14 @@ class ToolChain {
   using path_list = SmallVector<std::string, 16>;
 
   enum CXXStdlibType {
-    CST_Libcxx,
-    CST_Libstdcxx
+    CST_Libcxx,    // LLVM libc++
+    CST_Libstdcxx, // GNU libstdc++
+    CST_Msvcstl,   // MSVC STL
   };
 
-  enum RuntimeLibType {
-    RLT_CompilerRT,
-    RLT_Libgcc
-  };
+  enum RuntimeLibType { RLT_CompilerRT, RLT_Libgcc, RLT_Vcruntime };
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petrhosek wrote:

I think this should be spelled as `RLT_VCRuntime`.

https://github.com/llvm/llvm-project/pull/96417