The -fstack-usage option incorrectly calculate size of the stack used by a function

When calculating the size of the stack used by a function, the size of the stack does not include the size of the return address from the function. When compiling a file with any type of optimization, the size of the used stack becomes equal to 0, although it cannot be less than the return address.

```
size_test.cpp:3:_Z15simple_functionv 0 static
size_test.cpp:8:_Z16complex_functioni 0 static
size_test.cpp:17:_Z9factoriali 0 static
size_test.cpp:22:main 0 static
```

File su generated by GCC:
```
size_test.cpp:3:6:void simple_function() 8 static
size_test.cpp:8:6:void complex_function(int) 8 static
size_test.cpp:17:5:int factorial(int) 8 static
size_test.cpp:22:5:int main() 8 static
```