Building on Ubuntu 20.04

From your home directory:

Let get some packages:
sudo apt-get install build-essentials git liballegro5-dev
Now let's get the code:
git clone https://github.com/stardot/b-em.git
Switch to the project directory:
cd b-em
Build the executable:
./configure && make
Hopefully, time to run it:
./b-em