Check for lchflags properly.

attic/archiver.py

@@ -21,6 +21,7 @@ from attic.helpers import Error, location_validator, format_time, \
     is_cachedir, bigint_to_int
 from attic.remote import RepositoryServer, RemoteRepository
 
+has_lchflags = hasattr(os, 'lchflags')
 
 class Archiver:
 
@@ -159,7 +160,7 @@ Type "Yes I am sure" if you understand this and want to continue.\n""")
         if stat.S_ISSOCK(st.st_mode):
             return
         # Ignore if nodump flag set
-        if st.st_flags and (st.st_flags & stat.UF_NODUMP):
+        if has_lchflags and (st.st_flags & stat.UF_NODUMP):
             return
         self.print_verbose(remove_surrogates(path))
         if stat.S_ISREG(st.st_mode):