This post is now obsolete. You can install
tty-clock from the repository.
Tty-clock is a small program that displays a digital clock.
To compile it on Termux you'll need to download the sources from GitHub.
git clone https://github.com/xorg62/tty-clock.git
You'll also need the
apt install ncurses-dev
Sadly, compiling with
make doesn't really work with this one, I managed to compile it with the following command.
gcc -Wall -Werror -Wextra -std=c99 -pedantic -Wno-unused-parameter -lncurses -o tty-clock ttyclock.c
You can then install it with