AC_SEARCH_LIBS([clock_gettime], [rt], [], [AC_MSG_ERROR([*** POSIX RT library not found])])
AC_SEARCH_LIBS([cap_init], [cap], [], [AC_MSG_ERROR([*** POSIX caps library not found])])
AC_CHECK_HEADERS([sys/capability.h], [], [AC_MSG_ERROR([*** POSIX caps headers not found])])
AC_SEARCH_LIBS([clock_gettime], [rt], [], [AC_MSG_ERROR([*** POSIX RT library not found])])
AC_SEARCH_LIBS([cap_init], [cap], [], [AC_MSG_ERROR([*** POSIX caps library not found])])
AC_CHECK_HEADERS([sys/capability.h], [], [AC_MSG_ERROR([*** POSIX caps headers not found])])