[clang] [C23] Implement WG14 N3037 (PR #132939)

[Erich Keane via cfe-commits]

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@@ -11399,6 +11400,22 @@ static QualType mergeEnumWithInteger(ASTContext &Context, const EnumType *ET,
   return {};
 }
 
+QualType ASTContext::mergeTagTypes(QualType LHS, QualType RHS) {
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erichkeane wrote:

What about `mergeTagDefinitions`?  I don't have a good idea here otherwise, but it isn't really merging tag-types so much as just their definitions?

Also perhaps even in NOT the C2(whatever) mode: what about returning the 'not definition' (assuming 1 is a definition and 1 isnt?).  it makes it a no-op in that case, but perhaps one that is sensible.

https://github.com/llvm/llvm-project/pull/132939