eve.backend.kqueue.constants

Shared kqueue constants, types, and platform imports.

This module consolidates the kqueue kevent_t struct, EVFILT_*/EV_* constants, and platform-specific imports that are common across all kqueue-based platforms (macOS, FreeBSD, OpenBSD, NetBSD, DragonFly BSD).

On real kqueue platforms, the per-OS kevent module (eve.backend.macos.kevent or eve.backend.bsd.kevent) provides the compiler-header imports. If the compiler is too old to ship core.sys.*.sys.event headers, a set of manual definitions serves as fallback.

On platforms without kqueue support (Linux, Windows), a KqueueDummy stub is provided so that the module compiles without errors.