Is it possible to update the original struct/enum definitions themselves to be typedefs? For example,

typedef enum luarequire_NavigateResult
{
    NAVIGATE_SUCCESS,
    NAVIGATE_AMBIGUOUS,
    NAVIGATE_NOT_FOUND
} luarequire_NavigateResult;

I believe this should keep function signatures and call sites identical in C and in C++.

sure, I'll do that ASAP.

Sounds good, then we can also undo all these function signature changes. I believe it should just work in C as well.

implemented and tested against a C project

only issue I could find (that was masked by something else in my project) is that bool is not a standard keyword in C but that can be fixed/worked around by including stdbool.h first.

In that case, would you mind adding #include <stdbool.h> above the existing #include <stddef.h> (keeping them alphabetical)? I'll merge this after that.

Thanks for the contribution!