27.2.1. malloc
Allocate memory! Vs using the stack: https://stackoverflow.com/questions/4584089/what-is-the-function-of-the-push-pop-instructions-used-on-registers-in-x86-ass/33583134#33583134
userland/c/malloc.c: malloc hello world: allocate two ints and use them.
Linux 5.1 / glibc 2.29 implements it with the mmap system call.
malloc leads to the infinite joys of Memory leaks.