bgpd: add 'bgp bestpath as-path multipath-relax'

Compute multipath in BGP based on AS_PATH hop count match. If the knob
is turned on, it is not required to have an exact match of AS_PATHs
(provided other multipath conditions are met, of course).

Signed-off-by: Pradosh Mohapatra <pmohapat at cumulusnetworks.com>
Reviewed-by: Dinesh G Dutt <ddutt at cumulusnetworks.com>
Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
diff --git a/bgpd/bgpd.h b/bgpd/bgpd.h
index 0746f0d..024fedc 100644
--- a/bgpd/bgpd.h
+++ b/bgpd/bgpd.h
@@ -120,6 +120,7 @@
 #define BGP_FLAG_LOG_NEIGHBOR_CHANGES     (1 << 11)
 #define BGP_FLAG_GRACEFUL_RESTART         (1 << 12)
 #define BGP_FLAG_ASPATH_CONFED            (1 << 13)
+#define BGP_FLAG_ASPATH_MULTIPATH_RELAX   (1 << 14)
 
   /* BGP Per AF flags */
   u_int16_t af_flags[AFI_MAX][SAFI_MAX];