Fatal error: termio.h:

I want to migrate my image building from openwrt 15.05.1 to openwrt 21.02.0. In older building there are some custom library are present. Now I created these custom library in my latest build. But in latest build I am getting some error message like,
In file included from src/otdr_interface.c:10:
./inc/serial.h:11:10: fatal error: termio.h: No such file or directory
#include <termio.h>
compilation terminated.

When I compiled older openwrt build is successful. Can anyone suggest some solution, so that it will helpful to me.

Thanks in advance