setjmp/longjmp workaround using C++ exceptions

clang++.out

$ clang++ stack-manipulation-exception.cc
$ ./a.out
Entering stack_manipulate_func, level: 0
Normal execution path, level: 0
Entering stack_manipulate_func, level: 1
Throws exception at level 1
Error execution path, level: 0
Exiting stack_manipulate_func, level: 0

em++.out

$ ~/develop/mruby-browser/modules/emscripten/em++ -s EXCEPTION_DEBUG=0 stack-manipulation-exception.cc
$ node ./a.out.js
Entering stack_manipulate_func, level: 0
Normal execution path, level: 0
Entering stack_manipulate_func, level: 1
Throws exception at level 1
Error execution path, level: 0
Exiting stack_manipulate_func, level: 0

stack-manipulation-exception.cc

#include <stdio.h>

void stack_manipulate_func(int s, int level) {
  printf("Entering stack_manipulate_func, level: %d\n", level);

  if (level == 0) {
    try {
      printf("Normal execution path, level: %d\n", level);
      stack_manipulate_func(s, level + 1);
    } catch (int e) {
      printf("Error execution path, level: %d\n", level);
    }
  } else {
    printf("Throws exception at level %d\n", level);
    throw 1;
  }

  printf("Exiting stack_manipulate_func, level: %d\n", level);
}

int main(int argc, char *argv[]) {
  stack_manipulate_func(42, 0);

  return 0;
}