* lisp/term/ns-win.el (ns-selection-exists-p):
(gui-backend-set-selection):
(x-begin-drag): New functions and selection types.
* src/nsfns.m (Fns_get_resource):
(Fns_set_resource):
(Fx_server_max_request_size): Fix coding style.
* src/nsselect.m (ns_decode_data_to_pasteboard):
(ns_lisp_to_pasteboard):
(ns_dnd_action_to_operation):
(ns_dnd_action_from_operation):
(Fns_begin_drag): New functions.
(syms_of_nsselect): New subrs.
* src/nsterm.h (EmacsWindow): New fields and messages.
(NSPasteboardNameGeneral): New define.
* src/nsterm.m ([EmacsView mouseDown:]): Store last mouse event.
([EmacsWindow initWithEmacsFrame:fullscreen:screen:]): Clear that event.
([EmacsWindow dealloc]): Free last mouse event.

* src/xterm.c (x_parse_color): Update comment.
(syms_of_xterm): Add new debugging option too.

* src/xterm.c (handle_one_xevent): Reset valuators on XI_Leave
if leave->event is an edit widget as well.

* src/xterm.c (x_parse_color): Move recently used colors to the
start of the cache and free unused entries when there are too
many.
(x_term_init, x_delete_display): Initialize and free new fields.
* src/xterm.h (struct x_display_info): New field
`color_names_length'.

* src/haiku_support.cc (class EmacsMenuItem): Don't abort on
failed strdup.

* src/xterm.c (xm_drag_window_io_error_handler)
(x_dnd_io_error_handler): Use `siglongjmp'.  Reported by Ken
Brown <kbrown@cornell.edu>.

The bytecode interpreter can't directly call special forms, so
the byte-compiler usually converts special forms into some sequence of
byte codes (basically, providing a duplicate definition of the special
form).  There are still two exceptions to this: `defconst` and `defvar`,
where the compiler instead generates a convoluted chunk of code like:

    (funcall '(lambda (x) (defvar <sym> x <doc>)) <value>)

where the quote makes sure we keep the function non-compiled, so as
to end up running the special form at run time.

Get rid of this workaround by introducing `defvar-1` and `defconst-1`
which provide a *functional* interface to the functionality of the
corresponding special form.

* src/eval.c (defvar, Fdefvar_1, Fdefconst_1): New functions, extracted from
`Fdefvar` and `Fdefconst`.
(Fdefvar, Fdefconst): Use them.
(syms_of_eval): `defsubr` the new functions.

* lisp/emacs-lisp/bytecomp.el (byte-compile-tmp-var): Delete const.
(byte-compile-defvar): Simplify using the new functions.

* doc/lispref/variables.texi (Defining Variables): Adjust the doc of
`defvar` to reflect the actual semantics implemented.

* src/xterm.c (xm_side_effect_from_action): Handle
`XdndActionAsk'.
(xm_operations_from_actions): New function.
(xm_send_top_level_leave_message, x_dnd_cleanup_drag_and_drop)
(x_dnd_update_state, handle_one_xevent, x_connection_closed):
Use those actions when building a side effect.
(x_dnd_begin_drag_and_drop): Keep track of the set of
alternative drag-and-drop actions.

* src/xterm.c (x_trace_wire):
(x_term_init): Fix debugging code for modern C and Xlib.

* src/xterm.c (x_dnd_send_unsupported_drop, x_dnd_send_drop):
Use x_get_atom_name instead of XGetAtomName.