build下make失败这是什么回事？

[MonsterXS]

root@qiang:~/xkcptun/build# make [ 4%] Building C object CMakeFiles/xkcp_server.dir/xkcp_server.c.o /root/xkcptun/xkcp_server.c:36:26: fatal error: event2/event.h: No such file or directory

include <event2/event.h>

                      ^

compilation terminated. make[2]: [CMakeFiles/xkcp_server.dir/xkcp_server.c.o] Error 1 make[1]: [CMakeFiles/xkcp_server.dir/all] Error 2 make: *** [all] Error 2