+# 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 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/in.h
+dnl Check for netinet/in.h
+AC_CHECK_HEADERS([netinet/in.h])