[BUG]: register_exception is not global on MacOS

[gentlegiantJGC]

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What version (or hash if on master) of pybind11 are you using?

2.13.6

Problem description

On MacOS a C++ exception registered with py::register_exception will not be caught as the desired exception when raised from extension modules other than the one it was defined in.

In the following example I would expect a.throw_MyRuntimeError_a and b.throw_MyRuntimeError_b to raise a.MyRuntimeError.

This is the behaviour found on Windows and Linux but on MacOS b.throw_MyRuntimeError_b only raises python's RuntimeError. a.throw_MyRuntimeError_a works as expected.

Here is a pull request with tests on a repository with all the code required to reproduce this.
gentlegiantJGC/pybind11-crash#1

Reproducible example code

// my_runtime_error.hpp
#pragma once

#include <stdexcept>

class MyRuntimeError : public std::runtime_error {
public:
    using std::runtime_error::runtime_error;
};

// a.cpp
#include <pybind11/pybind11.h>

namespace py = pybind11;

#include "my_runtime_error.hpp"

PYBIND11_MODULE(a, m)
{
    py::register_exception<MyRuntimeError>(m, "MyRuntimeError", PyExc_RuntimeError);
    m.def("throw_MyRuntimeError_a", [](){ throw MyRuntimeError("MyRuntimeError_a"); });
}

// b.cpp
#include <pybind11/pybind11.h>

namespace py = pybind11;

#include "my_runtime_error.hpp"

PYBIND11_MODULE(b, m)
{
    m.def("throw_MyRuntimeError_b", [](){ throw MyRuntimeError("MyRuntimeError_b"); });
}

Is this a regression? Put the last known working version here if it is.

Unknown

[gentlegiantJGC]

Upon further investigation this is a duplicate of #2847