Squashed 'third_party/boostorg/container_hash/' content from commit 9fbda1a

Change-Id: I3db45eeb90d6b7e18fb95c2df04c0afc15541790
git-subtree-dir: third_party/boostorg/container_hash
git-subtree-split: 9fbda1a98a32498c52a1c8ebf62311bb36a44ad4
diff --git a/examples/books.hpp b/examples/books.hpp
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+
+// Copyright 2005-2009 Daniel James.
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+// This example illustrates how to use boost::hash with a custom hash function.
+// The implementation is contained in books.cpp
+
+#include <cstddef>
+#include <string>
+
+namespace library
+{
+    struct book
+    {
+        int id;
+        std::string author;
+        std::string title;
+
+        book(int i, std::string const& a, std::string const& t)
+            : id(i), author(a), title(t) {}
+    };
+
+    bool operator==(book const&, book const&);
+    std::size_t hash_value(book const&);
+}