I downloaded telegram open source code for android from the following the link https://github.com/DrKLO/Telegram. While importing the project am getting the following errors:<
The reason for your error is that the libtgvoip is a submodule and you did not clone the repository recursively so the required library has not been checked out.
To fix this go to the folder where you cloned the project and run
git submodule update --init --recursive
This will check out the required submodule