Get lib directories of Visual C++.

def get_lib(self, arch='x86'):
        """
        Get lib directories of Visual C++.
        """
        if arch == 'x86':
            arch = ''
        if arch == 'x64':
            arch = 'amd64'
        lib = os.path.join(self.vc_dir, 'lib', arch)
        if os.path.isdir(lib):
            logging.info(_('using lib: %s'), lib)
            return [lib]
        logging.debug(_('lib not found: %s'), lib)
        return []