fix blinking colons, inverse-video blocks, or specified character option

My current ncurses version is 5.9.

`-k`, `-c`, or `-v` doesn't actually update clock properly. `-k` shows no blinking, other two shows same time, clock never gets updated.

I am guessing there is some changes to `mvwin` to newer ncurses after those options were added, but I know nothing much about it, so I might but wrong and my fix might not be ideal.