Basic example. Creates a shared and a static library from a.c and b.c.
Used in the following answers:
- https://stackoverflow.com/questions/3961446/why-does-gcc-not-implicitly-supply-the-fpic-flag-when-compiling-static-librarie/65005457#65005457
- https://unix.stackexchange.com/questions/89211/how-to-test-whether-a-linux-binary-was-compiled-as-position-independent-code/435038#435038
- https://unix.stackexchange.com/questions/226524/what-system-call-is-used-to-load-libraries-in-linux/462710#462710