Add gmock into our dependencies.

third_party/boost/boost/type_traits/has_virtual_destructor.hpp

Index: third_party/boost/boost/type_traits/has_virtual_destructor.hpp
diff --git a/third_party/boost/boost/type_traits/has_virtual_destructor.hpp b/third_party/boost/boost/type_traits/has_virtual_destructor.hpp
new file mode 100644
index 0000000000000000000000000000000000000000..8f99ff420f39b4eeabd05db0f70e807ffabd64ee
--- /dev/null
+++ b/third_party/boost/boost/type_traits/has_virtual_destructor.hpp
@@ -0,0 +1,25 @@
+
+//  (C) Copyright John Maddock 2005.  
+//  Use, modification and distribution are subject to 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/libs/type_traits for most recent version including documentation.
+
+
+#ifndef BOOST_TT_HAS_VIRTUAL_DESTRUCTOR_HPP_INCLUDED
+#define BOOST_TT_HAS_VIRTUAL_DESTRUCTOR_HPP_INCLUDED
+
+#include <boost/type_traits/intrinsics.hpp>
+// should be the last #include
+#include <boost/type_traits/detail/bool_trait_def.hpp>
+
+namespace boost {
+
+BOOST_TT_AUX_BOOL_TRAIT_DEF1(has_virtual_destructor,T,BOOST_HAS_VIRTUAL_DESTRUCTOR(T))
+
+} // namespace boost
+
+#include <boost/type_traits/detail/bool_trait_undef.hpp>
+
+#endif // BOOST_TT_IS_MEMBER_FUNCTION_POINTER_HPP_INCLUDED