Makefile and build instructions

[andrewarrow]

Trying to build on a mac but need better README docs on how to run make or equivalent.

https://www.jetbrains.com/help/clion/cmakelists-txt-file.html#cmakelist-template

[kotborealis]

There's now a GIF demo on how to build this project, but yeah, I should include text instructions.
Right now you could read full_build.tape as a reference.

To build this project, you need to:

• clone this repo with submodules;
• run cmake -B./build and cmake --build ./build

I'm not sure if this will fully work on Mac, but at the very least you should be able to build _headless version, which does not depend on anything except source code and submodule.

[andrewarrow]

ah yes mac fails on /Users/aa/os/cassette_deck/src/x/x.h:2:10: fatal error: 'X11/Xatom.h' file not found