Files dependent on make_shared should include make_shared.hpp

Older boost versions did not include make_shared.hpp in smart_ptr.hpp, but we currently assume in the 26compat branch that the include of smart_ptr.hpp in pch.h will provide boost::make_shared.

Files dependent on make_shared should explicitly include the make_shared.hpp header.

Note that this does not affect legacy-0.8+ as pch.h was removed and make_shared.hpp added as needed throughout the codebase.