when compiling on ubuntu 18.04, the checker miss to check libevhtp, that will lead to report error during compiling phase than cmake check phase.

see below step:
1.
-- found libgpr.so --- works
-- found libwebsockets.h --- works
-- found libwebsockets.so --- works
-- found clibcni/api.h --- works
it is clear that the checker does not do libevhtp check. and there is no libevhtp installed on my system.

when compiling, the error shows below:
In file included from /home/xw/iSulad/src/http/rest_common.c:15:0:
/home/xw/iSulad/src/http/rest_common.h:18:10: fatal error: evhtp.h: No such file or directory
#include <evhtp.h>
^~~~~~~~~
compilation terminated.

So, during compiling phase, if the libevhtp is needed really, it should cmake do the check and report error than compiling phase.
if libevhtp is not necessary, it should be controlled by cmake system and deliver the info to makefile, the Makefile should bypass the libevhtp compiling path.