Merge in all changes from no-recursion branch.

Merge in all changes from no-recursion branch.

* src/remove.c (enum Ternary): Define type.
(prompt): Add a parameter.  Adjust callers.
(remove_entry): Attempt rmdir here, only if a directory is
`known' to be empty.  Significant rework.
(remove_dir): Propagate failure `up' also when rmdir fails.

In interactive mode, prompt only once about an empty directory.
* src/remove.c (enum Prompt_action): Define.
(prompt): Two new parameters.  Adjust all callers.

Performance.
* src/remove.c (remove_entry) [!ROOT_CAN_UNLINK_DIRS]:
Don't call rmdir here.

* src/remove.c (AD_pop_and_chdir): Don't use errno (it's not valid)
in diagnostic for changed dev/ino.
(remove_entry): Tweak diagnostic.

* src/remove.c (ROOT_CAN_UNLINK_DIRS): Define.
(AD_pop_and_chdir): Propagate status as we traverse back `up' the tree.
(DO_UNLINK, DO_RMDIR): Define.
(remove_entry) [ROOT_CAN_UNLINK_DIRS]: Add code so this works also on
systems where root can use `unlink' to remove directories.

* src/remove.c: Include file-type.h.
Include file type in prompt when asking whether to remove file.
Based on a patch from Paul Eggert.

* src/remove.c (prompt): Add comment.

* src/remove.c (remove_dir): Fix another (known) leak.

* src/remove.c (hash_freer): New function.
(AD_mark_helper): Use it.
(AD_mark_as_unremovable): xstrdup the filename argument.
(remove_dir): Free directory name.

* src/remove.c (remove_entry): Fail also when trying to remove a
directory without the --recursive option.
Change a diagnostic, s/unlink/remove/, now that it can apply also
to a directory.

* src/remove.c (is_empty_dir): New function.
(prompt): New function, factored out of...
(remove_entry): ...here.  Call it.
(remove_dir): Call prompt before rmdir.

* src/remove.c (remove_entry): Add support for prompting (e.g., -i).

* src/remove.h (UPDATE_STATUS): New macro.
* src/remove.c [AD_ent] (status): New member.  This lets us propagate
the status from a subdirectory to its parent via AD_pop_and_chdir.
(AD_push_initial): Set it.
(AD_push): Likewise.
(remove_cwd_entries): Change return type to enum RM_status, and
adjust all callers.
(rm): Use UPDATE_STATUS rather than open-coding it.

* src/remove.c (remove_entry): New function, factored out of...
(remove_cwd_entries): ...here, and...
(rm_1): ...here.

* src/remove.c (remove_cwd_entries): Add support for --verbose.
(remove_dir): Likewise.
(rm_1): Likewise.

* src/remove.c (rm): Free cwd_state, if necessary.

* src/remove.c (rm_1): Remove now useless (always true)
user_specified_name parameter.  Adjust sole caller.

* src/remove.c (rm): New function.  This interface allows
one to remove multiple arguments at a time.  This is important in
that it allows us to hide the remove_init/remove_fini functions and
the cwd_state parameter.
(rm_1): Renamed from rm.
(remove_init, remove_fini): Remove functions.  Each body is now
part of `rm'.