[modules] Number anonymous declarations that are lexically within mergeable
contexts, so that we can merge them when we merge the surrounding context.

llvm-svn: 216639
diff --git a/clang/lib/Serialization/ASTCommon.h b/clang/lib/Serialization/ASTCommon.h
index 5374197..b6488a2 100644
--- a/clang/lib/Serialization/ASTCommon.h
+++ b/clang/lib/Serialization/ASTCommon.h
@@ -80,6 +80,10 @@
 /// \brief Determine whether the given declaration kind is redeclarable.
 bool isRedeclarableDeclKind(unsigned Kind);
 
+/// \brief Determine whether the given declaration needs an anonymous
+/// declaration number.
+bool needsAnonymousDeclarationNumber(const NamedDecl *D);
+
 } // namespace serialization
 
 } // namespace clang