Merge pull request #65058 from cachemeifyoucan/eng/PR-swift-cas-fs

[CAS] Integrate CAS into swift compiler

include/swift/Basic/LangOptions.h

@@ -804,6 +804,9 @@ namespace swift {
     /// import, but it can affect Clang's IR generation of static functions.
     std::string Optimization;
 
+    /// clang CASOptions.
+    std::string CASPath;
+
     /// Disable validating the persistent PCH.
     bool PCHDisableValidation = false;