Add gmock into our dependencies.

third_party/boost/boost/preprocessor/stringize.hpp

Index: third_party/boost/boost/preprocessor/stringize.hpp
diff --git a/third_party/boost/boost/preprocessor/stringize.hpp b/third_party/boost/boost/preprocessor/stringize.hpp
new file mode 100644
index 0000000000000000000000000000000000000000..64dd5fde3e3cd837cff7c057dfb9a47aec1d21e7
--- /dev/null
+++ b/third_party/boost/boost/preprocessor/stringize.hpp
@@ -0,0 +1,33 @@
+# /* Copyright (C) 2001
+#  * Housemarque Oy
+#  * http://www.housemarque.com
+#  *
+#  * 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)
+#  */
+#
+# /* Revised by Paul Mensonides (2002) */
+#
+# /* See http://www.boost.org for most recent version. */
+#
+# ifndef BOOST_PREPROCESSOR_STRINGIZE_HPP
+# define BOOST_PREPROCESSOR_STRINGIZE_HPP
+#
+# include <boost/preprocessor/config/config.hpp>
+#
+# /* BOOST_PP_STRINGIZE */
+#
+# if BOOST_PP_CONFIG_FLAGS() & BOOST_PP_CONFIG_MSVC()
+#    define BOOST_PP_STRINGIZE(text) BOOST_PP_STRINGIZE_A((text))
+#    define BOOST_PP_STRINGIZE_A(arg) BOOST_PP_STRINGIZE_I arg
+# elif BOOST_PP_CONFIG_FLAGS() & BOOST_PP_CONFIG_MWCC()
+#    define BOOST_PP_STRINGIZE(text) BOOST_PP_STRINGIZE_OO((text))
+#    define BOOST_PP_STRINGIZE_OO(par) BOOST_PP_STRINGIZE_I ## par
+# else
+#    define BOOST_PP_STRINGIZE(text) BOOST_PP_STRINGIZE_I(text)
+# endif
+#
+# define BOOST_PP_STRINGIZE_I(text) #text
+#
+# endif