Fix cmsghdr struct for the *nixes

Previously we had a single definition of std.c.cmsghdr for all
libc-linking platforms which aliased from the Solaris definition,
a superfluous matching one in std.os.dragonfly, and no others.

The existing definition from std.c didn't actually work for Linux,
as Linux's "len" field is usize in the kernel's definition.

Emscripten follows the Linux model of course (but uses the
binary-compatible musl definition, which has an endian-sensitive
padding scheme to make the len type "socklen_t" even though the
kernel uses a usize, which is fair).

This unifies and documents all the known *nix-ish cases (I'm not
sure if wasi or windows really has cmsghdr support? Could be added
later, void for now), such that c.cmsghdr and posix.system.cmsghdr
should work correctly for all the known cases here, libc or
otherwise.

0 files changed, 0 insertions, 0 deletions