Thank you! I hope you'll enjoy the new developments.
The build scripts expect both SDL2 and A2 to be properly installed in the development environment, like any other libraries - so the typical procedure is to build and install SDL2, then build and install A2, and finally, the game.
Correct - but the Makefiles (as generated by CMake) should take care of all that normally. I suppose you can't use my shell scripts out of the box, but CMake, GNU make etc should work fine on most platforms.