Building on nix

[purepani]

Hi,
I'm trying to use this package in NixOS, and from what I can tell, this package isn't using the wrapper than nix has for the CPP compiler to make this work. I just wanted to get some pointers to how cxx compiles the code to see if I can figure out how to inject the wrapper correctly(we have a hook to do this with bindgen by using the BINDGEN_CFLAGS variable, but I'm not sure what the cxx equivalent of that would be).
Appreciate any help!