David Dubbeldam
The Apple M1 chip is based on the ARM instruction set. To compile for the M1, add the target flag to the llvm compiler
To compile for x86_64 on the Apple M1 use the following flag
To see the architectures present in a built executable file, run the lipo command-line tool
To generate an universal binary, use the lipo command-line tool
Note that the same command applies to generate universal static libraries.