Remove the meaningless on Linux if_dl.h header.

This was misleading 'configure' into thinking we actually support AF_LINK,
but we're Linux, so we don't, and we never implemented the functions we
declared here either.

Reported to AOSP by Jun-ya Kato.

Change-Id: I111f9887f3812469b411b9cf5124d9dd624f19f7
2 files changed