To use TelegramGLib on Android you need latest version of Termux app.
Don't use Termux from GooglePlay, it's outdated and will not work!
You can download it from Github or F-Droid
2 Build TelegramGLib
$ pkg update
and press Enter
when prompted
$ pkg install git python3 valac libsoup3 json-glib cmake ninja gobject-introspection
and press Enter
when prompted
$ pip3 install meson
$ git clone https://github.com/SpikedPaladin/TelegramGLib
$ cd TelegramGLib
$ meson setup --prefix=/data/data/com.termux/files/usr build
$ cd build
$ ninja install
Wait until compilation finished
Now you can use TelegramGLib to run bot on your Android phone
Example:
$ vala --pkg telegram-glib-0.3 /path/to/your/vala/file