Recall that in Chapter 3 we pointed out that “hello world” is actually a complex program, although most of the complexity is “under the hood.” Finally, we will show how to compile libc in a manner that minimizes the memory requirements (especially SRAM). If you’re going to use libc on an STM32 variant with substantial SRAM (at least 20k) this step is unnecessary – you may use the libraries distributed with the Sourcery tools.