All three of you are wrong. :/
With Linux variants, you want to use pkg-config to compile and link your program.
That tutorial is out dated as well.
Switch to branch 5.0 for the latest stable release
git checkout 5.0
Preparing for build
mkdir build; cd build
That's wrong. You want 'git checkout master' or 'git checkout 5.2.3'. 5.2.4 is coming out somewhat soon as well.
To compile, you add /usr/local/include to your search directory for the compiler.
To link, you add /usr/local/lib to your search directory for the linker.
To get the compiler options allegro was built with, use :
`pkg-config --cflags allegro5`
and to get the linker options you need to specify, use :
`pkg-config --libs allegro5`
So, a complete invocation with gcc would be :
gcc -Wall -Wextra -o runme `pkg-config --cflags allegro_monolith-5` main.c other.c `pkg-config --libs allegro_monolith-5`
You need to have pkg-config installed when you build allegro.