Building on Ubuntu

LibTLS

Telescope requires libtls which is not packaged for Ubuntu yet. It's available as libtls20 and libtls-dev on Sid, so it will eventually come to Ubuntu too. In the meantime, obtain libtls-dev.deb and libtls20.deb from https://packages.debian.org/bookworm/source/libretls, and manually install using

sudo dpkg -i libtls20.deb
sudo dpkg -i libtls-dev.deb

or build them from source.

Read about the confusing naming of the libraries involved.

Other dependencies

You may need to install other libraries, such as libevent-dev, if the configure script shows missing dependencies.