In file included from /usr/include/sys/types.h:25,
                 from headtest_util_h.c:1:
/usr/include/features.h:413:4: warning: #warning _FORTIFY_SOURCE requires compiling with optimization (-O) [-Wcpp]
  413 | #  warning _FORTIFY_SOURCE requires compiling with optimization (-O)
      |    ^~~~~~~
headtest_util_h.c:2:10: fatal error: util.h: No such file or directory
    2 | #include <util.h>
      |          ^~~~~~~~
compilation terminated.