Temporarily fix the oclosure bootstrap

* lisp/emacs-lisp/oclosure.el (oclosure-define): Load oclosure
from source if `oclosure--define' is not defined during byte
compilation.

Don't loop through useless region when searching for DND toplevel

* src/xterm.c (x_dnd_compute_toplevels): Optimize for the
bounding rect being the window dimensions.

Add search function to search within filenames in Dired and WDired (bug#14013)

* lisp/dired-aux.el (dired-isearch-filenames-mode): Use
dired-isearch-search-filenames on isearch-search-fun-function
instead of dired-isearch-filter-filenames on isearch-filter-predicate.
(dired-isearch-filter-filenames): Remove function.
(dired-isearch-search-filenames): Add function.

* lisp/isearch.el (isearch-message-prefix): Add isearch-search-fun-function
to the list of supported advice-functions along with isearch-filter-predicate.

* lisp/replace.el (replace-search): Add comment.

* lisp/wdired.el (wdired-search-replace-filenames): New defcustom.
(wdired-isearch-filter-read-only): Remove function.
(wdired-change-to-wdired-mode, wdired-change-to-dired-mode):
Add and remove dired-isearch-search-filenames on isearch-search-fun-function
instead of wdired-isearch-filter-read-only on isearch-filter-predicate.
Also set/unset replace-search-function and replace-re-search-function.
Remove and restore isearch-mode-hook with dired-isearch-filenames-setup.
The problem is that dired-isearch-filenames-setup adds
dired-isearch-filenames-end to isearch-mode-end-hook that removes
dired-isearch-search-filenames added to isearch-search-fun-function
in wdired-change-to-wdired-mode.  Then replace-highlight can't use
dired-isearch-search-filenames.

Add OClosures, a cross between functions and structs

We here just add the new type.  It is not fully self-contained.
It requires cooperation from `cconv.el` on the one hand, and it
hijacks the docstring info to hold the type of OClosure objects.
This does imply that OClosures can't have docstrings, tho this
limitation will be lifted in subsequent patches.

* lisp/emacs-lisp/oclosure.el: New file.
* test/lisp/emacs-lisp/oclosure-tests.el: New file.
* doc/lispref/functions.texi (OClosures): New section.

* src/eval.c (Ffunction): Accept symbols instead of strings for docstrings.
* src/doc.c (store_function_docstring): Avoid overwriting an OClosure type.
* lisp/emacs-lisp/cconv.el (cconv--convert-function): Tweak ordering of
captured variables.
(cconv-convert): Add case for `oclosure--fix-type`.

Fix doc of `gui-get-selection' as to what is really valid as `data'

* doc/lispref/frames.texi (Window System Selections):
* lisp/select.el (gui-set-selection): Don't say `data' can be a
cons or list of two integers, since that's not supported.

Minor fixes to Haiku selection support

* lisp/term/haiku-win.el (haiku-selection-bounds): New function.
(haiku-dnd-convert-string, haiku-select-encode-xstring)
(haiku-select-encode-utf-8-string): Handle position pairs
correctly.
(gui-backend-set-selection): Adjust for new airity.
* src/haikuselect.c (Fhaiku_selection_put): Fix arity.

Improve portability of XCB configure checks

* configure.ac: Look for xcb_aux_sync in -lxcb-aux if it's not
in -lxcb-util.

Do not register Tramp file name handlers twice

* lisp/net/tramp.el (tramp-register-autoload-file-name-handlers):
* lisp/net/tramp-archive.el (tramp-register-archive-file-name-handler):
Check, whether the real file name handler is already registered.

Avoid extra sync when fetching DND proxy window

* src/xterm.c (x_dnd_get_proxy_proto): New function.
(x_dnd_get_target_window): Use it on XCB to determine window
proxy and proto for toplevel window.

Clean up some uses of XInternAtom

* src/xfns.c (x_set_undecorated, x_set_no_focus_on_map, x_window)
(set_machine_and_pid_properties): Move calls to XInternAtom for
static string to use previously interned atoms.
(Fx_change_window_property): Use XCB if available to avoid extra
call to XSync.
* src/xterm.c (x_term_init):
* src/xterm.h (struct x_display_info): New atoms _MOTIF_WM_HINTS
and _NET_WM_PID.

; * src/xterm.c (x_dnd_compute_toplevels): Use right enum on XCB.

Store latin-1 content into the Haiku clipboard as well

* lisp/term/haiku-win.el (haiku-normal-selection-encoders): New
variable.
(haiku-select-encode-utf-8-string, haiku-select-encode-xstring):
New functions.
(gui-backend-set-selection): Use new selection encoder functions
instead of hard-coding UTF-8.
(haiku-dnd-handle-drag-n-drop-event): Rename to
`haiku-drag-and-drop'.

* src/haiku_select.cc (be_lock_clipboard_message): Accept new
argument `clear'.
(be_unlock_clipboard): Accept new argument `discard'.

* src/haikuselect.c (Fhaiku_selection_data): Change calls to
`be_lock_clipboard_message' and `be_unlock_clipboard'.
(haiku_unwind_clipboard_lock): New function.
(Fhaiku_selection_put): Accept new meaning of `name' which means
to set the selection message.

* src/haikuselect.h: Update prototypes.

Clean up PGTK cursor blanking code

* src/pgtkterm.c (XTframe_rehighlight): Rename to
`pgtk_frame_rehighlight_hook'.  All callers changed.
(x_toggle_visible_pointer): Rename to
`pgtk_toggle_visible_pointer'.  All callers changed.
(x_setup_pointer_blanking, XTtoggle_invisible_pointer): Delete
functions.
(pgtk_create_terminal): Use new names for various hooks.
(pgtk_term_init): Set up blank cursor directly.

* src/pgtkterm.h (struct pgtk_display_info): Remove
`toggle_visible_pointer'.

Don't wait for XdndFinished messages if the target did not send status

* src/xterm.c (x_dnd_send_leave): Return if we should wait for a
XdndFinished message.
(handle_one_xevent): Use that value for
`x_dnd_waiting_for_finish'.

Always run 'isearch-lazy-count-update-hook' with point at match

* lisp/isearch.el (isearch-lazy-highlight-buffer-update):  Run
'isearch-lazy-count-update-hook' outside of save-excursion, so point
is at the current match.

Fix processing of DND grab on non-XI2 builds

* src/xterm.c (handle_one_xevent): Process DND grab flag
correctly.

Merge from origin/emacs-28

1bef52ce73 * doc/emacs/anti.texi (Antinews): Unannounce removal of Mo...

Fix no-toolkit build

* src/xterm.c (x_top_window_to_frame): Declare correctly on
no-toolkit builds.

Avoid excessive synchronization when handling ShapeNotify events

* src/xterm.c (handle_one_xevent): Use XCB to handle ShapeNotify
events when we want both the bounding and input rects.

; * src/haikuimage.c (syms_of_haikuimage): Remove duplicate DEFSYM.

Fix reader infinite recursion for circular mixed-type values

Make sure that the value added to the `read_objects_completed` set is
the one we actually return; previously this wasn't the case for conses
because of an optimisation (bug#54501).

Also add a check for vacuous self-references such as #1=#1# instead of
returning a nonsense value from thin air.

* src/lread.c (read1): Treat numbered conses correctly as described
above.  Detect vacuous self-references.
* test/src/lread-tests.el (lread-test-read-and-print)
(lread-test-circle-cases, lread-circle): Add tests.

; * src/image.c (syms_of_image): Fix whitespace.

Enable the native display of BMP images on Haiku

* src/image.c (syms_of_image): Also register `bmp' image type on
Haiku when native image APIs are enabled.

Fix crash when timer signals or throws inside a popup menu on Haiku

* src/haikumenu.c (haiku_process_pending_signals_for_menu_1)
(haiku_process_pending_signals_for_menu_2): New functions.
(haiku_process_pending_signals_for_menu): Catch non local exits
around `timer_check'.

; * src/xterm.c (x_dnd_compute_toplevels): Fix cookie leak if rc is 0.

Fix processing of emacs:window_id inside DND messages if it already exists

* src/haiku_support.cc (MessageReceived): Use DropPoint instead
of getting it manually.
(be_drag_message): Replace window_id if it already exists.

; Improve readablity in grep.el

* lisp/progmodes/grep.el (grep-compute-defaults): Set a more
readable value for `grep-quoting-style'.

Don't let Tramp block dired  (Bug#54542)

* lisp/dired.el (dired-find-buffer-nocreate): Avoid avoid hangs in
remote buffers with a blocked connection.  (Bug#54542)

* lisp/net/tramp-sh.el (tramp-maybe-open-connection):
Extend suppression rules.

Minor fixes to last change

* src/Makefile.in: Add XSHAPE_LIBS and XSHAPE_CFLAGS.
(LIBES, EMACS_CFLAGS): Likewise.

* src/xterm.c (x_dnd_compute_toplevels): Fix build without
HAVE_XCB_SHAPE.

Also fetch shapes via XCB for drag and drop

* configure.ac: Also look for xcb-shape.
* src/xterm.c (HAVE_XCB_SHAPE_INPUT_RECTS): New define.
(x_dnd_compute_toplevels): Use XCB for input shapes if possible.

Use native image APIs on MS-Windows by default

* src/w32term.c (syms_of_w32term) <w32-use-native-image-API>: Now
t by default on W2K and later systems, but only on WINDOWSNT
builds.

* etc/NEWS: Announce the change.

Support display of BMP images on MS-Windows

* src/w32image.c (w32_can_use_native_image_api): Support BMP
images.
* src/image.c (syms_of_image) <Qbmp>: New symbol.
[HAVE_NTGUI]: Add 'bmp' to list of supported image types.

* doc/lispref/display.texi (Image Formats): Document built-in
support for BMP images.

* etc/NEWS: Announce the change.

Improve 'desktop--emacs-pid-running-p'

* lisp/desktop.el (desktop--emacs-pid-running-p): Avoid false
negatives on MS-Windows and with some symlinks to Emacs
executables.  (Bug#1474)

* doc/emacs/anti.texi (Antinews): Unannounce removal of Motif.

Merge from origin/emacs-28

4ec9f9edd1 Fix eshell-explicit-command-char doc string typo

Fix crash when windows are destroyed by faulty clients

* src/xterm.c (x_dnd_compute_toplevels): Make sure
property_reply is non-NULL before testing its format and length.

Avoid excessive synchronization when initiating drag-and-drop

* src/xterm.c (x_dnd_compute_toplevels): Use XCB to get WM
state, attributes, geometry and to translate coordinates.  This
avoids 4 calls to XSync.

Fix compiler warning in x-dnd.el

* lisp/x-dnd.el (x-dnd-xdnd-to-action): Move declaration
earlier.

Avoid ClientMessage overhead when dragging stuff to other frames

* lisp/dired.el (dired-mouse-drag): Handle correctly dragging
from dired buffers in nonselected windows.
* lisp/x-dnd.el (x-dnd-handle-drag-n-drop-event): Understand new
client message type.
* src/xterm.c (x_dnd_send_enter, x_dnd_send_position)
(x_dnd_send_leave): Ignore if window is the top window of a
frame.
(x_dnd_send_drop): Send special DND event in that case.

Fix minor issues with dired-mouse-drag-files

* lisp/dired.el (dired-mouse-drag-files): Update doc string and
add setter.
(dired-insert-set-properties): Don't insert misleading tooltip
if feature is not available.

; * lisp/gnus/nnselect.el (nnselect-get-artlist): Fix last change.

; Restore regexp-quote for gnus subject match

* lisp/gnus/gnus-sum.el (gnus-summary-limit-include-thread): Restore
regexp-quote that was inadvertently dropped in commit 2021-12-21 "Fix
gnus subject matching when subject is empty".

Fix eshell-explicit-command-char doc string typo

* lisp/eshell/esh-ext.el (eshell-explicit-command-char): Fix typo
in doc string (bug#54567).

Fix (bounds-of-thing-at-point 'number)

* lisp/thingatpt.el (number): Make (bounds-of-thing-at-point
'number) work (bug#54555).

Fix reporting of read error line/columns in the init file

* src/lread.c (invalid_syntax_lisp): The comments here said that
we were supposed to be called with point in the readcharfun
buffer.  This was not the case (at least) when reading the Emacs
init file, so the reported line/column was always wrong (1 and 0,
respectively) (bug#54550).

Improve pp-last-sexp ergonomics

* lisp/emacs-lisp/pp.el (pp-last-sexp): Ignore ,@?
before a sexp, because eval-ing that will always lead to an error
(bug#54537).

Implement new drag and drop parameter on Haiku

* lisp/term/haiku-win.el (x-begin-drag): Implement
`allow-current-frame'.
* src/haiku_support.cc (be_drag_message): New argument
`allow_same_view'.
* src/haiku_support.h: Update prototypes.
* src/haikuselect.c (Fhaiku_drag_message): New parameter
`allow-same-frame'.

Allow dragging files from dired to windows on the same frame

* doc/lispref/frames.texi (Drag and Drop): Document new
parameter to `x-begin-drag'.
* lisp/dired.el (dired-mouse-drag): Utilize new parameter.
* lisp/term/haiku-win.el (x-begin-drag): Add new parameter.
* src/xfns.c (Fx_begin_drag): New parameter
`allow-current-frame'.  Fix typo and update doc string.
* src/xterm.c (x_dnd_get_window_proto): Respect
`x_dnd_allow_current_frame'.
(x_dnd_begin_drag_and_drop): New parameter
`allow_current_frame'.
* src/xterm.h: Update prototypes.

Improve documentation of 'completion-auto-select'

* lisp/simple.el (completion-auto-select):
* doc/emacs/mini.texi (Completion Options): Improve documentation
and description of customization options of 'completion-auto-select'.

Make it easier to select text inside dired when mouse dragging is on

* lisp/dired.el (dired-insert-set-properties): Only set drag
keymap on the filename itself.

* admin/notes/emba: Mention workflow rules for branches.

Fix quitting DND while waiting for finish

* src/xterm.c (x_dnd_begin_drag_and_drop): Always clear finish
flag before quitting.

Take window shapes into account when processing drag and drop

* configure.ac: Test for the Nonrectangular Window Shape
extension.
* msdos/sed1v2.inp: Update.
* src/xterm.c (struct x_client_list_window): New fields for
shapes.
(x_dnd_free_toplevels): Free shapes.
(x_dnd_compute_toplevels): Populate window shapes.
(x_dnd_get_target_window_2): New function.
(x_dnd_get_target_window_1): Test WM state of window before
taking it into account.
(x_dnd_begin_drag_and_drop): Use outer window as the initial
last seen window.
(x_dnd_update_state): Small fixes to frame tracking.
(handle_one_xevent): Handle ShapeNotify events correctly.
(x_term_init): Test for the Nonrectangular Window Shape
extension.
* src/xterm.h (struct x_display_info): New atom `WM_STATE'.

Merge from origin/emacs-28

d3d6f1c9bd Clarify the description of "selected tags table"

Use _NET_CLIENT_LIST_STACKING to optimize drag and drop window discovery

* src/xterm.c (struct x_client_list_window): New struct.
(x_dnd_free_toplevels, x_dnd_compute_toplevels)
(x_dnd_get_target_window_1): New functions.
(x_dnd_get_target_window): Search in the toplevel list if it
exists.
(x_dnd_cleanup_drag_and_drop): Clean up toplevel list.
(x_dnd_begin_drag_and_drop): Compute toplevel list if the
window manager supports it.
(handle_one_xevent): Update the toplevel list if prudent.

Fix wrapping of 'previous-completion' at the beginning of buffer

* lisp/simple.el (next-completion): Prevent an error of
'previous-completion' at the beginning of completions buffer.
Also fix 'previous-completion' to wrap to the last completion.
(bug#54374)

Small fixes for the new feature 'second-tab' of 'completion-auto-select'

* lisp/simple.el (completion-auto-select): Extend the docstring.

Clarify the description of "selected tags table"

* doc/emacs/maintaining.texi (Select Tags Table): Clarify the
distinction between the "selected tags table" and the "current
list of tags tables".  (Bug#54543)

Handle invisible text in Eldoc when calculating size

Co-authored-by: João Távora <joaotavora@gmail.com>
* lisp/emacs-lisp/eldoc.el (eldoc--echo-area-substring,
eldoc-display-in-echo-area):  Take invisible text into consideration
when counting lines to crop an echo-area message.
(Version): Bump.

; * etc/NEWS: Fix wording of a recently added entry.

Allow fetching events from other displays inside DND

* src/xterm.c (x_dnd_begin_drag_and_drop): Get the next event
from the app connection instead on Xt.

; Fix filename in undigest-tests.el header

Adapt Tramp to dired--insert-disk-space assumptions

* lisp/net/tramp-sh.el (tramp-sh-handle-insert-directory):
* lisp/net/tramp-smb.el (tramp-smb-handle-insert-directory):
Do not modify disk space information when
`dired--insert-disk-space' is available.  (Bug#54512)

Fix autoinsert.el byte compilation warning

* lisp/autoinsert.el (sgml-tag): Fix a byte compilation warning.

Merge 'completion-auto-select new value secont-tab'

This includes the second-tab value for completion-auto-select and
documentation related.

Add documentation entries for completion-auto-select user option.

Add completion-auto-select second-tab value.

* lisp/minibuffer.el (completion--in-region-1) : Change if with cond and
check if completion-auto-select.
* lisp/simple.el (completion-auto-select) : Move before first use.
(completion-setup-function) : Make a more precise check for when
completion-auto-select is t.

* lisp/select.el (xselect-convert-to-targets): Use `delete-dups` and `delq`

* lisp/autoinsert.el (auto-insert-alist): Expose lambdas as code

(archive-*-write-file-member): Fix relative file name

* lisp/arc-mode.el (archive-*-write-file-member): Set the pwd

Do some NEWS tagging

Avoid crashes if async input arrives when setting properties for DND

* src/xterm.c (x_dnd_begin_drag_and_drop): Block input around
non-async signal safe functions.

Mention frame-text-* function in frame-pixel-* doc strings

* src/frame.c (Fframe_native_width, Fframe_native_height): Link to
`frame-text-*' functions.

Fix image-mode-fit-frame some more

* lisp/image-mode.el (image-mode-fit-frame): Use frame-text-width
and fit-frame-to-buffer instead of computing things ourselves
(bug#37630).  This makes things work better across platforms.

Fix some bugs with drag and drop and Mozilla

* src/xfns.c (Fx_begin_drag): Call maybe_quit when iterating
through potentially long lists.  Also allow specifying
XdndActionAsk manually again, since it's useful for debugging.
* src/xterm.c (x_dnd_begin_drag_and_drop): Delete XdndActionList
and XdndActionDescription if they were not specified.

Load desktop without prompting if process is dead

* doc/emacs/misc.texi (Saving Emacs Sessions): Document the new
'check' value.
* etc/NEWS: Announce the change (bug#1474).
* lisp/desktop.el (desktop-load-locked-desktop): Add new value 'check'
to load desktop file without prompting if locking Emacs process does
not exist on the local machine.  (Bug#1474)
(desktop-read): Extract function from here...
(desktop--load-locked-desktop-p): ...to here.  New function handles
the semantics of 'desktop-load-locked-desktop', including above new
value 'check'.
(desktop--emacs-pid-running-p): New function.

* test/lisp/desktop-tests.el: New file with tests for the above.

Fix setter for hl-line-sticky-flag when hl-line is not loaded

* lisp/hl-line.el (hl-line-sticky-flag): Wrap most of setter
around (featurep 'hl-line).  Reported by Michael Heerdegen
<michael_heerdegen@web.de>.

Allow holding down scroll bar buttons on Haiku when overscrolling

* src/haiku_support.cc (EmacsWindow): Set appropriate pulse
rate.
(class EmacsScrollBar, ValueChanged): Don't send any part events
here.
(MouseDown): Set dragging to a value larger than 1 if the scroll
bar is at the end.
(Pulse): New method.

Fix an infinite loop if the window manager pings Emacs during DND

* src/xterm.c (handle_one_xevent): Work around _NET_WM_PING
infinite loop during drag and drop.

Fix copying font names around on Haiku

* src/haiku_font_support.cc (font_style_to_flags)
(haiku_font_fill_pattern, BFont_open_pattern)
(BFont_populate_fixed_family, BFont_populate_plain_family):
* src/haiku_support.cc (be_get_version_string):
* src/haikufont.c (haikufont_spec_or_entity_to_pattern): Stop
assuming patterns were allocated by xzalloc.

Allow dragging and dropping multiple actions

* doc/lispref/frames.texi (Drag and Drop): Document new meaning
of `action'.
* lisp/term/haiku-win.el (x-begin-drag): Correct for new meaning
of `action'.
* src/xfns.c (Fx_begin_drag): Handle new alist meaning of
`action'.
* src/xterm.c (x_dnd_begin_drag_and_drop): New parameters
`ask_action_list', `ask_action_names' and `n_ask_actions'.
* src/xterm.h: Update prototypes.

Fix regression in isearch-yank-char-in-minibuffer

* lisp/isearch.el (isearch-yank-char-in-minibuffer): Select the
original window in order to restore point.  This is needed when
minibuffer lazy highlight is in effect.

Make undigest work with multipart/mixed messages

* test/lisp/mail/undigest.el: New test file (bug#12873).
* lisp/mail/undigest.el (rmail-digest-methods): Install
rmail-digest-parse-mixed-mime.
(rmail-content-type-boundary): New function, to get a specific
Content-type boundary.
(rmail-digest-parse-mixed-mime): New function, to search for a
multipart/digest message inside a multipart/mixed message.

Make quoting of shell arguments in grep.el more robust

* lisp/progmodes/grep.el (grep-apply-setting)
(grep-compute-defaults): Adapt docstring.
(grep-quoting-style): New variable.
(grep-compute-defaults, grep-default-command)
(grep-expand-keywords, lgrep, rgrep-default-command): Use it.

* doc/misc/eudc.texi (Inline Query Expansion): Unbreak it.

Support changing remoteness of DIR in rgrep and lgrep

* lisp/net/tramp-sh.el (tramp-get-remote-dev-tty): New defun.
(tramp-sh-handle-make-process): Use it.

* lisp/progmodes/grep.el: Prefer #' to quote named functions.
(lgrep, rgrep): Recompute grep defaults when the remoteness of DIR
changes.

Improvements to Haiku selection handling

* lisp/term/haiku-win.el (haiku-selection-targets): Implement in Lisp.
* src/haiku_select.cc (be_get_message_type):
(be_set_message_type):
(be_get_message_message):
(be_add_message_message): New functions.

* src/haiku_support.cc (MessageReceived): Fix typo.
* src/haikuselect.c (haiku_selection_data_1)
(Fhaiku_selection_targets): Delete functions.
(haiku_message_to_lisp, lisp_to_type_code)
(haiku_lisp_to_message): Correctly decode and encode nested
messages, and fix encoding specially decoded types via numeric
names.  Also store and decode message types inside Lisp
messages.
(Fhaiku_drag_message): Update doc string.
(syms_of_haikuselect): Update subrs.
* src/haikuselect.h: Update prototypes.

Reinstate `C-M-<delete>'

* lisp/bindings.el (global-map): Reinstate `C-M-<delete>' and
`C-M-<backspace>' (bug#29430).  These used to kill X, but that
hasn't been the case in any common GNU/Linux distributions for
decades.

Fix image-mode-fit-frame resizing

* lisp/image-mode.el (image-mode-fit-frame): Use pixel sizes
instead of lines/columns to get more accurate resizing (bug#37630).

* lisp/term/pgtk-win.el: Update header comment.

Fix hl-line tests

* lisp/hl-line.el (hl-line-mode): Restore old setter.
* test/lisp/hl-line-tests.el (hl-line-tests-verify): Don't rely
`cl-some' always returning t on success.
(hl-line-tests-sticky-across-frames): Use correct global variable.

* lisp/calendar/todo-mode.el: Restore old code.

Restore old hl-line code

* lisp/hl-line.el: Restore old code to remove obsoletions.
(hl-line-overlay-priority): Make defcustom.

Allow retrieving some more kinds of clipboard data on Haiku

* src/haiku_select.cc (BClipboard_find_data): Handle NULL
characters inside data correctly.
(be_lock_clipboard_message, be_unlock_clipboard): New functions.
* src/haikuselect.c (Fhaiku_selection_data): Return entire
clipboard contents as a message when clipboard is NULL.
(haiku_lisp_to_message): Allow quitting when iterating through
potentially large or circular lists.
* src/haikuselect.h (enum haiku_clipboard): New enum.

; Merge from origin/emacs-28

The following commit was skipped:

c69a617742 Add notes about command modes and nativecomp interaction

Fix crash in haiku_message_to_lisp

* src/haikuselect.c (haiku_message_to_lisp): Block input around
`free'.

Handle quitting correctly during interprogram drag-and-drop

* lisp/mouse.el (mouse-drag-and-drop-region): Handle quit
correctly by exiting the cross program drag and drop.

* src/xterm.c (x_dnd_begin_drag_and_drop): Fix test against DND frame.

Don't allocate duplicate cursors for each frame on Haiku

* src/haikufns.c (haiku_create_frame)
(haiku_free_frame_resources): Stop creating cursors.
* src/haikuterm.c (haiku_delete_terminal, haiku_term_init):
Create and free cursors here instead.
* src/haikuterm.h (struct haiku_display_info): New fields for
cursors.

Improve DND documentation

* doc/lispref/frames.texi (Drag and Drop):
* src/xfns.c (Fx_begin_drag): Document meaning of
`XdndActionPrivate'.