Building on Ubuntu 20.04

It is best to make sure your system is up to date first then open a terminal.
from your home directory.
Let get some packages:
sudo apt-get install build-essential 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:
./autogen.sh && ./configure && make
If you have a multi-core processor you can cut the build time by using -j, for example:
make -j4
as the final part of the above. Hopefully, time to run it:
./b-em