Update compiler.py

Solves error generated by using sys.maxint constant in Python 3.1.5^, sys.maxsize is available for use in Python 2.0.0.

Python docs for reference:
- sys.maxint deprecated in Python 3.1.5^: https://docs.python.org/3.1/whatsnew/3.0.html#integers
- sys.maxsize supported in Python 2.6^ : https://docs.python.org/2.6/library/sys.html#sys.maxsize