GCC

Compilation for ARM64 (AArch64)

Install the package:

$ sudo apt install gcc-aarch64-linux-gnu

Then, we can compile it:

$ arm-linux-gnueabi-gcc-9 main.c -o main_arm64
$ readelf -a elf_arm64 | grep "Machine"
  Machine:                           AArch64

Compilation for ARM32

Install the package following:

$ sudo apt install gcc-9-arm-linux-gnueabi

Then, you can compile it:

$ arm-linux-gnueabi-gcc-9 main.c -o main_arm
$ eadelf -a elf_arm | grep "Machine" 
  Machine:                           ARM