_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

首先檢查 CPython PR #108605，以及 TensorStore 的 python/tensorstore/future.cc 第 105 行中對 _PyOS_SigintEvent 的使用。追蹤移除公開標頭檔宣告會如何影響擴充函式庫，並比較可用的訊號喚醒替代方案。完成的標準是為函式庫提供一種受支援的方式，使其能夠中斷主執行緒上的同步等待，同時保留 Ctrl+C 的行為。