Also show mouse DND tooltip contents during interprogram drag-and-drop

* doc/lispref/frames.texi (Drag and Drop): Document new
parameter to `x-begin-drag'.
* lisp/mouse.el (mouse-drag-and-drop-region): Don't hide tooltip
when initiating interprogram drag-and-drop.
* lisp/term/haiku-win.el (x-begin-drag):
* lisp/term/ns-win.el (x-begin-drag): Add stubs for new
parameter.
* src/xfns.c (Fx_begin_drag): New parameter `follow-tooltip'.
(Fx_show_tip, syms_of_xfns): Add records of the last dx and dy
given to `x-show-tip'.
* src/xterm.c (x_clear_dnd_monitors): New function.
(x_dnd_begin_drag_and_drop): Save monitor attributes list if
appropriate.
(x_dnd_compute_tip_xy, x_dnd_update_tooltip_position): New
function.
(x_dnd_update_state, handle_one_xevent): Update tooltip position
during DND mouse movement.
(syms_of_xterm): Update staticpros.
* src/xterm.h: Update prototypes.

2 files changed, 4 insertions, 2 deletions

diff --git a/lisp/term/haiku-win.el b/lisp/term/haiku-win.el
index 6ddf546ee57..58217513902 100644
--- a/lisp/term/haiku-win.el
+++ b/lisp/term/haiku-win.el
@@ -366,7 +366,8 @@ take effect on menu items until the menu bar is updated again."
 
 (setq haiku-drag-track-function #'haiku-dnd-drag-handler)
 
-(defun x-begin-drag (targets &optional action frame _return-frame allow-current-frame)
+(defun x-begin-drag (targets &optional action frame _return-frame
+                             allow-current-frame _follow-tooltip)
   "SKIP: real doc in xfns.c."
   (unless haiku-dnd-selection-value
     (error "No local value for XdndSelection"))
diff --git a/lisp/term/ns-win.el b/lisp/term/ns-win.el
index 2e021b9b29c..0d46a895ce8 100644
--- a/lisp/term/ns-win.el
+++ b/lisp/term/ns-win.el
@@ -895,7 +895,8 @@ See the documentation of `create-fontset-from-fontset-spec' for the format.")
                                          &context (window-system ns))
   (ns-get-selection selection-symbol target-type))
 
-(defun x-begin-drag (targets &optional action frame return-frame allow-current-frame)
+(defun x-begin-drag (targets &optional action frame return-frame
+                             allow-current-frame _follow-tooltip)
   "SKIP: real doc in xfns.c."
   (unless ns-dnd-selection-value
     (error "No local value for XdndSelection"))