A minimal no_std program

#![no_main]
#![no_std]
use core::panic::PanicInfo;
#[panic_handler]
fn panic(_panic: &PanicInfo) -> ! {
    loop {}
}

• This will compile to an empty binary.
• std provides a panic handler; without it we must provide our own.
• It can also be provided by another crate, such as panic-halt.
• Depending on the target, you may need to compile with panic = "abort" to avoid an error about eh_personality.
• Note that there is no main or any other entry point; it’s up to you to define your own entry point. This will typically involve a linker script and some assembly code to set things up ready for Rust code to run.