[PATCH] bits/socket.h: Define struct sockaddr with may_alias attribute [BZ #19622]

[Florian Weimer]

On 02/12/2016 02:15 PM, Florian Weimer wrote:
> It is quite common to use struct sockaddr * as an opaque, void *-like
> type for socket addresses.  The POSIX API encourages to some degree.
> Marek Polacek suggested to add the may_alias attribute to the definition
> of struct sockaddr.
> 
> Support for that was introduced in GCC 4.0, so I added a conditional to
> cdefs.h.

I've been told off-list to move the attribute right after the struct,
and this is the version I will commit if approved.

This patch is a result of the Fedora mass rebuild with GCC 6, where we
now see a lot of warnings related to this (potential) aliasing violation.

Florian