hghave: fix clang-format check to use bytes regex
Fixes hghave on Python 3.
Differential Revision: https://phab.mercurial-scm.org/D1182
#!/usr/bin/env python
from __future__ import absolute_import, print_function
import errno
import os
import sys
for f in sys.argv[1:]:
try:
print(f, '->', os.readlink(f))
except OSError as err:
if err.errno != errno.EINVAL:
raise
print(f, '->', f, 'not a symlink')
sys.exit(0)