file that hasn't really been created.

NO_SYMLINK_XATTRS is defined.

If a symlink, device, special-file, or hard-linked file is replacing
an existing non-directory, the new file is created using a temporary
filename and then renamed into place.  Also changed the handling of
a cluster of hard-linked symlinks/devices/special-files to always
ensure the first item in the cluster is correct, since it doesn't
really save any significant work to try to find an existing correct
item later in the cluster to link with.

Fixes bug 6569.

Inspired by the patch to bug 6633.

Patch from Tim Spriggs.

writing a batch file.

for each file given on the command-line.

that is based on the master in the new "based-on:" line.

- Improve function name: parse_rule -> parse_filter_str (to make the
  similarity with parse_filter_file clearer, and better indicate that
  it can parse multiple rules when FILTRULE_WORD_SPLIT is specified).

- In preparation for rule prefixes containing information beyond the
  rflags, change the code to pass around a full "template" filter_rule
  instead of just rflags.  Callers of parse_filter_{str,file} that want
  to specify only rflags can use rule_template(rflags) .

- Remove the MODIFIERS_* strings and instead hand-code the condition
  under which each modifier is valid.  This should make it easier to
  see that the conditions are correct.

- Tighten up default modifiers on merge rules:
  - Disallow "!" because it isn't useful.
  - If the merge rule specifies a side via "s" or "r", the rules in the
    file cannot also specify a side via "s", "r", "hide", etc.

[Patch was changed by Wayne a bit prior to application.]

function for the latter, it will always exist).