_PyOS_SigintEvent() is needed for interruptible waiting on main thread

Bug report

Bug description:

Moved from https://github.com/python/cpython/pull/108605#issuecomment-2521215855

In https://github.com/python/cpython/pull/108605, _PyOS_SigintEvent was removed from the public headers.

TensorStore relies on that function here: https://github.com/google/tensorstore/blob/eda046b10158e7d82fdb0f23aeecdfdeb8ac5aa3/python/tensorstore/future.cc#L105 to enable synchronously blocking on the readiness of a custom Future type while allowing Ctrl+C to interrupt when running on the main thread.

The current workaround is to manually declare the function since the symbol is still available.

I'm not aware of a usable alternative. Since signal.set_wakeup_fd only allows a single fd to be set globally, it isn't usable from a library. The best alternative would probably be to poll by waking up every few hundred milliseconds.

CPython versions tested on:

3.13

Operating systems tested on:

No response

Comience revisando CPython PR #108605 y el uso de _PyOS_SigintEvent en python/tensorstore/future.cc de TensorStore, en la línea 105. Trace cómo afecta a las bibliotecas de extensión la eliminación de la declaración del encabezado público y compare las alternativas disponibles para despertar mediante señales. Se considerará terminado cuando se proporcione una forma compatible para que una biblioteca interrumpa la espera síncrona en el hilo principal, preservando el comportamiento de Ctrl+C.