[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++" {
+// CHECK-NEXT:   int f(int);
+// CHECK-NEXT:   int g(int);
+// CHECK-NEXT: }
+extern "C++" int f(int), g(int);
+
+// CHECK: extern "C" {
+// CHECK-NEXT:  void foo();
+// CHECK-NEXT:  int x;
+// CHECK-NEXT:  int y;
+// CHECK-NEXT: }
+extern "C" {
+  void foo(void);
+  int x, y;
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erichkeane wrote:

This part in particular is unfortunate.  What do we look like in non-linkage specs?

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