Support LibreSSL 4.1.x

[toxadx]

OpenBSD 7.7 was released yesterday, including LibreSSL 4.1.x. Compilation of openssl-sys is currently handled through patching in the build system, but it would be better to add native support for it directly in openssl-sys

[botovq]

This can be done once LibreSSL 4.1.0 is released, which should happen soon.