Add simple way to include header only libraries

[DeanHnter]

Description

Currently (i might be wrong) it seems theres no simple way to just directly inject a preprocessor directive such as include. Defines etc are covered, but if i want to simply #include <mylib.h> it needs to be handled at the project level? Based on the documentation iv read anyway. It would be nice to have a decorator or something that just adds the header include to the top of the file produced to avoid requiring project settings when writing wrappers.

@nativedefine("banana")
def banana(a: int, b: int, c:int) -> int:
    pass

@nativeheader("mylib")

Again im aware that you can modify the carpentr file etc but its slightly more confusing to come back to after weeks.