import os
import sys
import re
import distutils.util
from distutils.sysconfig import get_config_var, get_config_vars
from distutils.command.config import config
from glob import glob
from os.path import join
from stat import ST_MTIME

def check_packages(packages, msg, include_ase, import_numpy):
    """Check the python version and required extra packages

    If ASE is not installed, the `packages` list is extended with the
    ASE modules if they are found."""

    if sys.version_info < (2, 3, 0, 'final', 0):
        raise SystemExit('Python 2.3.1 or later is required!')

    if import_numpy:
        try:
            import numpy
        except ImportError:
            raise SystemExit('numpy is not installed!')
    else:
        msg += ['* numpy is not installed.',