I'm attempting to compile the SOP_Star example of the HDK on:
Houdini 20.0.506
OS X Sonoma (14.1)

I've run into a problem related to std::unary_function which is used in hboost (hash.hpp). It appears that this function was deprecated in c++17, and the deprecated support was removed in OSX 14.

Traditionally I've developed on Linux, but I'm trying this on my fancy Mac Mini. I'm not really sure what the best option is here. Should I:
1) Use the _LIBCPP_ENABLE_CXX17_REMOVED_UNARY_BINARY_FUNCTION compile flag to reactivate the deprecated functionality
2) Patch hash.hpp in hboost
3) Something else that I don't know about

It doesn't look like it's convenient to downgrade back to OSX 13. This is my first experience writing code for Mac, and I'm not sure what the my options are here. Are there any others who have already worked through this that could offer some advice?

Log a bug. In the mean time, I think adding -D_LIBCPP_ENABLE_CXX17_REMOVED_UNARY_BINARY_FUNCTION to your compiler flags is your best bet.