games/xray_re-tools: unbreak the port's build against Clang 16

Both std::const_mem_fun1_t' and std::binary_function' template
classes had been deprecated in C++11 and removed in C++17, let's
get rid of them: the latter is just some typedefs and the former
holds a pointer to a member function and provides `operator()'.

Reported by: pkg-fallout