tests: fix Makefile.am so it works with BSD make

The export statement is specific to GNU make and breaks the build
with BSD make. I couldn't observe any difference in behaviour
between having the export present and absent, therefore, just remove it.

Signed-off-by: Christian Franke <chris@opensourcerouting.org>
tests: don't build tests unless make check is run

Use check_PROGRAMS instead of noinst_PROGRAMS in tests/Makefile.am
to build the tests only when make check is actually run.

Signed-off-by: Christian Franke <chris@opensourcerouting.org>
Merge branch 'buildsystem-tests' into osr/master
zebra: rework recursive route resolution

Change the datastructure for recursive routes. This brings the following
benefits:

By using struct nexthop also to store nexthops obtained by recursive
resolution, we can get rid of quite a bit of code duplication in the fib
management. (rt_netlink, rt_socket, ...)

With the new datastructure we can make use of all available paths when
recursive routes are resolved with multipath routes.

Signed-off-by: Christian Franke <chris@opensourcerouting.org>
zebra: handle blackholes encountered in recursive resolution

Signed-off-by: Christian Franke <chris@opensourcerouting.org>
zebra: implement NEXTHOP_FLAG_ONLINK

On Linux, the kernel will only allow for a route to be installed when
its gateway is directly attached according the kernel fib.

There are cases when this restriction by the kernel is too strong, in
those cases, we deploy the RTNH_F_ONLINK netlink flag.

Signed-off-by: Christian Franke <chris@opensourcerouting.org>
zebra: fix recursive-routes via ifindex routes

Signed-off-by: Christian Franke <chris@opensourcerouting.org>
zebra: apply route-maps for interface routes

Signed-off-by: Christian Franke <chris@opensourcerouting.org>
Merge branch 'recursive-multipath' into osr/master