[clang] [clang][AST] fix ast-print of `extern <lang>` with >=2 declarators (PR #93131)

[Erich Keane via cfe-commits]

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@@ -0,0 +1,27 @@
+// RUN: %clang_cc1 -ast-print %s -o - | FileCheck %s
+
+// CHECK: extern "C" int printf(const char *, ...);
+extern "C" int printf(const char *...);
+
+// CHECK: extern "C++" {
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erichkeane wrote:

We don't really have much guarantees besides 'best effort', so I am querying Aaron to see if this is 'good enough'.  Just `VarDecl` isn't going to be sufficient (probably something in `DeclStmt` handling?) because we can have any sorts of declarations this way.

https://github.com/llvm/llvm-project/pull/93131