zebra: fix rtadv detection

The GLIBC macro tests were just plain wrong. Glibc 2.1 is ancient
and the support should be detected via configure.ac test, not
macro test. Build with HAVE_RTADV but !RTADV is broke after vrf,
so for now, just define RTADV always if HAVE_RTADV is there.

Signed-off-by: Timo Teräs <timo.teras@iki.fi>
1 file changed