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