[PATCH,HURD] comment out PF_LINK/AF_LINK

[Paul Eggert]

On 06/22/2012 11:22 AM, Roland McGrath wrote:> Programs should just use
> proper checks for what they use (i.e. an autoconf-style check for 'struct
> sockaddr_dl' or the header that defines it), rather than #ifdef AF_*.

Although the autoconf style produces more-portable code, it's still
nicer if glibc also works with programs that use the #ifdef strategy,
as that makes it easier on developers who code just for glibc platforms.
#ifdefs are simpler and are much faster at build time.

Although the proposed patch isn't strictly necessary, it does seem like a
minor improvement.