#26 Fix incompatible pointer types error

[Ahmed El-Mahmoudy]

When building against gcc 15, there were some incompatible pointer type errors. The attached patch fixes this

[Araki Ken]

Thanks. I fixed it.
https://github.com/arakiken/mlterm/commit/dfca8d8c98f64dba5a7fede46cd3b3bbb1fc4633