* add backend/mcast to build

src/backends/CMakeLists.txt

@@ -4,6 +4,9 @@ set(BACKENDS "")
 add_library("f2b_backend_exec" MODULE "exec.c" "../strlcpy.c")
 list(APPEND BACKENDS "f2b_backend_exec")
 
+add_library("f2b_backend_mcast" MODULE "mcast.c" "../strlcpy.c"
+  "../commands.c" "../cmsg.c" "../csocket.c")
+
 find_library(REDIS_FOUND "hiredis")
 if (WITH_REDIS AND REDIS_FOUND)
   add_library("f2b_backend_redis" MODULE "redis.c" "../strlcpy.c")