Static local variable support

[ForNeVeR]

We should support static local variables properly, i.e.

void incrementAndPrint(void) {
  static int counter = 0;
  ++counter;
  printfn("%d", counter);
}

int main(void) {
  incrementAndPrint(); // 1
  incrementAndPrint(); // 2
}

Look for number 342 in the sources when implementing this feature.