MacOS M1 cross compile and build a fat binary with aarch64/arm64 and x86_64/amd64

build.sh

#!/bin/bash

clang hello.c -target arm64-apple-darwin20.1.0 -o hello.arm64
echo -n "hello.arm64 is architecture " && lipo -archs ./hello.arm64

clang hello.c -target x86_64-apple-darwin-macho -o hello.x86_64
echo -n "hello.x86_64 is architecture " && lipo -archs ./hello.x86_64

lipo  hello.arm64 hello.x86_64  -create -output hello
echo -n "final output binary has archs " && lipo -archs ./hello

hello.c

#include <stdio.h>

int main(void) {
    puts("Hello, world!");
    return 0;
}