dnl Check for poll.h
AC_CHECK_HEADERS([poll.h])
+# check for unistd.h
+dnl Check for unistd.h
+AC_CHECK_HEADERS([unistd.h])
+
+# check for sys/ioctl.h
+dnl Check for sys/ioctl.h
+AC_CHECK_HEADERS([sys/ioctl.h])
+
# check for SA_LEN
dnl Check if sockaddr data structure includes a "sa_len"
AC_CHECK_MEMBER([struct sockaddr.sa_len],