[hurd,commited] hurd sendmsg: Fix warning on calling CMSG_*HDR

[Samuel Thibault]

Andreas Schwab, le dim. 29 déc. 2019 18:12:02 +0100, a ecrit:
> > -  for (; cmsg; cmsg = CMSG_NXTHDR (message, cmsg))
> > +  for (; cmsg; cmsg = CMSG_NXTHDR ((struct msghdr *) message, cmsg))
> 
> Why is the first argument of __cmsg_nxthdr not const?

I don't know, it is so on other systems as well.

I guess an issue is that if it was const, CMSG_NXTHDR would only
be allowed to return a const, and the caller might actually want a
non-const (and it passed a non-const). So it'd be a choice between
cast-parameter vs cast-returned-value.

Samuel