[clang] [C++26][clang] Implement P2795R5 'Erroneous behaviour for uninitialized reads' (PR #177614)

[Erich Keane via cfe-commits]

================
@@ -432,6 +439,7 @@ def SYCLHost : LangOpt<"SYCLIsHost">;
 def SYCLDevice : LangOpt<"SYCLIsDevice">;
 def COnly : LangOpt<"", "!LangOpts.CPlusPlus">;
 def CPlusPlus : LangOpt<"CPlusPlus">;
+def CPlusPlus26 : LangOpt<"CPlusPlus26">;
----------------
erichkeane wrote:

See above, I don't think we should do this.

https://github.com/llvm/llvm-project/pull/177614