[clang] [clang][C23] Support N3029 Improved Normal Enumerations (PR #103917)

[Aaron Ballman via cfe-commits]

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@@ -6194,9 +6195,12 @@ def err_misplaced_ivar : Error<
 def warn_ivars_in_interface : Warning<
   "declaration of instance variables in the interface is deprecated">,
   InGroup<DiagGroup<"objc-interface-ivars">>, DefaultIgnore;
-def ext_enum_value_not_int : Extension<
-  "ISO C restricts enumerator values to range of 'int' (%0 is too "
-  "%select{small|large}1)">;
+def ext_c23_enum_value_not_int : Extension<
+  "enumerator values exceeding range of 'int' are a C23 extension (%0 is too "
+  "%select{small|large}1)">, InGroup<C23>;
+def warn_c17_compat_enum_value_not_int : Warning<
+  "enumerator values exceeding range of 'int' are incompatible with C standards before C23 (%0 is too "
+  "%select{small|large}1)">, DefaultIgnore, InGroup<CPre23Compat>;
----------------
AaronBallman wrote:

We could add another `%select` in here:
```
def ext_c23_enum_value_not_int : Extension<
  "%select{|incremented }0enumerator value which exceeds the range of 'int' is a C23 extension (%1 is too "
  "%select{small|large}2)">, InGroup<C23>;
```
WDYT?

https://github.com/llvm/llvm-project/pull/103917