+# check for poll.h
+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 netdb.h
+dnl Check for netdb.h
+AC_CHECK_HEADERS([netdb.h])
+
+# check for utime.h
+dnl Check for utime.h
+AC_CHECK_HEADERS([utime.h])
+
+# check for net/if.h
+dnl Check for net/if.h
+AC_CHECK_HEADERS([net/if.h])
+
+# check for sys/time.h
+dnl Check for sys/time.h
+AC_CHECK_HEADERS([sys/time.h])
+
+# check for sys/ioctl.h
+dnl Check for sys/ioctl.h
+AC_CHECK_HEADERS([sys/ioctl.h])
+
+# check for sys/vfs.h
+dnl Check for sys/vfs.h
+AC_CHECK_HEADERS([sys/vfs.h])
+
+# check for sys/statvfs.h
+dnl Check for sys/statvfs.h
+AC_CHECK_HEADERS([sys/statvfs.h])
+
+# check for sys/socket.h
+dnl Check for sys/socket.h
+AC_CHECK_HEADERS([sys/socket.h])
+
+# check for netinet/tcp.h
+dnl Check for netinet/tcp.h
+AC_CHECK_HEADERS([netinet/tcp.h])
+
+# check for netinet/in.h
+dnl Check for netinet/in.h
+AC_CHECK_HEADERS([netinet/in.h])
+
+# check for arpa/inet.h
+dnl Check for arpa/inet.h
+AC_CHECK_HEADERS([arpa/inet.h])