FreeBSD use a `size_t` for the `len` argument, while other UNIX-likes
use an `unigned int`.

From a quick glance, Windows does not have the equivalent syscall in the
WinSock API.

This one is great. The whole unix world uses an int for the flags, and
documents it as such. But musl uses an unsigned int there [1], while
still documenting a signed int.

This API is cursed.

[1]: https://git.musl-libc.org/cgit/musl/tree/include/sys/socket.h?id=39838619bb8b65a8897abcfda8c17ad6de0115d8#n70

…latforms

For some braindead reason, old versions of android on 32 bit  defined
socklen_t to be an int, instead of the unsigned int it was everywhere
else.