Invalid string name returned on uint8_t-derived enum with entries larger than 0x7F

[rndtrash]

Compiler: gcc (Ubuntu 15.2.0-4ubuntu4) 15.2.0, C++ version set to 20.

Here is a minimal reproducible example of the issue:

#include <cstdint>
#include <iostream>
#include <fix8/conjure_enum.hpp>

template <FIX8::valid_enum T>
std::string enum_to_string(T value)
{
    return std::string(FIX8::conjure_enum<T>::enum_to_string(value));
}

enum Repro : uint8_t {
	kExpected = 0x01,
	kInvalid = 0x80,
};

int main() {
    const auto val = Repro::kExpected;
    std::cout << "The name of " << +static_cast<uint8_t>(val)
    	<< " is " << enum_to_string(val) << std::endl;

    return 0;
}

Expected output:

The name of 1 is kExpected

Got:

The name of 1 is kInvalid

If kInvalid is set to anything less (like 0x7F or 0x10), then the program above works as expected.

[rndtrash]

Could be fixed by defining this macro in the global scope:

FIX8_CONJURE_ENUM_SET_RANGE_INTS(Repro, 0, 255);

It's still weird that the library always assumes a signed underlying type, though.