Expected behavior

swift-nio builds and is usable on FreeBSD and OpenBSD, especially since FreeBSD is an official platform for Swift 6.2

Actual behavior

Various build failures, around lock types (pthread_mutex_t vs pthread_mutex_t?) and LITTLE_ENDIAN ifdefs in c_nio_sha1.c.

Steps to reproduce

1. swift build

If possible, minimal yet complete reproducer code (or URL to code)

n/a

SwiftNIO version/commit hash

HEAD.

System & version information

Please provide at the very least your operating system and Swift version
information.

Swift 6.2.0, OpenBSD, but will also likely be a problem on FreeBSD.