cbindgen export the constants from Rust to C
So that we do not have 2 definitions on the 2 sides
Which can end up having a different value
That is the line item_types = ["enums","structs","opaque","functions"] in rust/cbindgen.toml
cbindgen doesn't like our BIT_ macros, maybe there is a work-around, maybe not. In Rust bit flags are often written out like 0b00000001.
This would lead us more to a big super include. Should we care? I noticed I can run cbindgen aginst particular .rs files to make more granular header files which might be something to explore as well...