Add gmock into our dependencies.

third_party/boost/boost/preprocessor/iteration/detail/self.hpp

Index: third_party/boost/boost/preprocessor/iteration/detail/self.hpp
diff --git a/third_party/boost/boost/preprocessor/iteration/detail/self.hpp b/third_party/boost/boost/preprocessor/iteration/detail/self.hpp
new file mode 100644
index 0000000000000000000000000000000000000000..757185c1f27e467776567a1df1041b73d56ca9b6
--- /dev/null
+++ b/third_party/boost/boost/preprocessor/iteration/detail/self.hpp
@@ -0,0 +1,21 @@
+# /* **************************************************************************
+#  *                                                                          *
+#  *     (C) Copyright Paul Mensonides 2002.
+#  *     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)
+#  *                                                                          *
+#  ************************************************************************** */
+#
+# /* See http://www.boost.org for most recent version. */
+#
+# if !defined(BOOST_PP_INDIRECT_SELF)
+#    error BOOST_PP_ERROR:  no indirect file to include
+# endif
+#
+# define BOOST_PP_IS_SELFISH 1
+#
+# include BOOST_PP_INDIRECT_SELF
+#
+# undef BOOST_PP_IS_SELFISH
+# undef BOOST_PP_INDIRECT_SELF