Here's what works on my Mac, compiled with clang -m32.

  #include <stdio.h>
  
  int main() {
  	int i;                                // Another stack variable
  	printf("%s\n", **(char ***)(&i + 8)); // argv[0]
  	return 0;
  }

Of course, this won't work at all on x86_64 because arguments are passed on registers instead of the stack.