Rename interval_node -> itree_node, interval_tree -> itree_tree,
interval_tree_order -> itree_order.

* src/alloc.c: Renames.
* src/buffer.c: ditto.
* src/itree.c: ditto.
* src/itree.h: ditto.
* src/lisp.h: ditto.
* src/pdumper.h: ditto.
* src/textprop.h: ditto.
* src/xdisp.h: ditto.

Correct `get-char-property` which failed to ignore empty overlays.

* src/textprop.c (get_char_property_and_overlay): Make sure the
overlay covers the character.
* test/src/buffer-tests.el (buffer-tests--overlay-bug58479): New test.
* src/buffer.h (buffer_has_overlays): Avoid `interval_tree_size`.

When Emacs-25 changed the default of `inhibit-point-motion-hooks` to t,
/etc/NEWS declared it as obsolete and so did its docstring, but
it was not marked as obsolete so as not to emit too many warnings
in code where it was impractical to remove the let-binding while
keeping backward compatibility with older Emacsen.
Those backward compatibility issues are not serious any more now that
Emacs-25 is itself considered old.

* lisp/subr.el (inhibit-point-motion-hooks): Mark it as obsolete.
* src/textprop.c (inhibit-point-motion-hooks): Don't mention it being
obsolete in the docstring any more.
* lisp/simple.el (line-move-1, line-move-finish): Silence warnings.

* src/itree.h (interval_tree_iter_start): Adjust type.
(interval_tree_nodes): Delete declaration.
(ITREE_FOREACH, ITREE_FOREACH_ABORT, ITREE_FOREACH_NARROW): New macros.

* src/itree.c (interval_tree_contains, interval_tree_insert_gap):
Use the new ITREE_FOREACH macro.
(interval_tree_nodes): Delete function.
(interval_tree_iter_start): Return the iterator.
(interval_generator_next, interval_tree_destroy):
Don't accept a NULL arg any more.

* src/xdisp.c (load_overlay_strings, strings_with_newlines):
* src/textprop.c (get_char_property_and_overlay):
* src/buffer.c (copy_overlays, delete_all_overlays)
(set_overlays_multibyte, swap_buffer_overlays, overlays_in)
(next_overlay_change, previous_overlay_change, overlay_touches_p)
(overlay_strings, Foverlay_lists, report_overlay_modification)
(evaporate_overlays): Use the new ITREE_FOREACH macro.

* src/buffer.h (buffer_overlay_iter_start1)
(buffer_overlay_iter_start, buffer_overlay_iter_next)
(buffer_overlay_iter_finish, buffer_overlay_iter_narrow):
Delete declarations.

* src/lisp.h (modiff_incr): Add a parameter to 'modiff_incr' to record
the extent of the modification.

* src/insdel.c (insert_1_both, insert_from_string_1, insert_from_gap,
insert_from_buffer_1, adjust_after_replace, replace_range,
replace_range_2, del_range_2, modify_text): Add an argument to each
call to 'modiff_incr'.

* src/textprop.c (modify_text_properties): Add an argument to the call
to 'modiff_incr'.

* src/buffer.c (Frestore_buffer_modified_p, Fbuffer_swap_text,
modify_overlay): Add an argument to each call to 'modiff_incr'.

* src/xdisp.c (redisplay_window): Use the improved version of 'MODIFF'
for the heuristic.

* doc/lispref/lists.texi (Plist Access): Document it.

* lisp/filesets.el (filesets-reset-fileset)
(filesets-ingroup-cache-get):
(filesets-ingroup-cache-put):
(filesets-build-menu-now): Don't use lax-plist functions.

* lisp/simple.el (lax-plist-put, lax-plist-get): Moved here from
fns.c and make obsolete.

* lisp/emacs-lisp/byte-opt.el (side-effect-free-fns): Don't mark
plist functions as side-effect-free or pure.

* lisp/emacs-lisp/comp.el (comp-known-type-specifiers): Adjust type.

* lisp/emacs-lisp/shortdoc.el (list): Don't document deprecated
functions.

* src/xdisp.c (build_desired_tool_bar_string):
(display_mode_element):
(store_mode_line_string):
(display_string):
(produce_stretch_glyph):
(note_mode_line_or_margin_highlight):
(note_mouse_highlight):
* src/w32.c (serial_configure):
* src/sysdep.c (serial_configure):
* src/sound.c (parse_sound):
* src/process.c (Fset_process_buffer):
(Fset_process_sentinel):
(Fprocess_contact):
(Fmake_process):
(Fmake_pipe_process):
(Fset_network_process_option):
(Fserial_process_configure):
(Fmake_serial_process):
(set_network_socket_coding_system):
(finish_after_tls_connection):
(connect_network_socket):
(Fmake_network_process):
(server_accept_connection):
* src/lread.c (ADDPARAM):
(hash_table_from_plist):
* src/keyboard.c (make_lispy_position):
* src/indent.c (check_display_width):
* src/image.c (postprocess_image):
* src/gnutls.c (gnutls_verify_boot):
(Fgnutls_boot):
(gnutls_symmetric):
(Fgnutls_hash_mac):
(Fgnutls_hash_digest):
* src/dired.c (filter):
* src/data.c (add_to_function_history):
* src/coding.c (Fcoding_system_put): Adjust callers from
Fplist_put (etc) to plist_put.

* src/fns.c (plist_get):
(plist_put):
(plist_member): New functions (without optional third parameter)
to be used in C code.

* src/fns.c (Fplist_get, Fplist_put, Fplist_member): Take an
optional predicate parameter (bug#47425).

* src/lisp.h: Declare new plist_put, plist_get and plist_member
functions.

* test/lisp/json-tests.el (test-json-add-to-plist): Use plist-get.

* test/src/fns-tests.el (test-cycle-lax-plist-get):
(test-cycle-lax-plist-put):
(lax-plist-get/odd-number-of-elements):
(test-plist): Remove lax-plist tests, since semantics have changed
(they no longer error out on cycles).

* src/alloc.c (deadp):
* src/buffer.c (reset_buffer_local_variables, candidate_buffer)
(Fkill_buffer, Fbuffer_swap_text, Fmake_overlay, Fmove_overlay):
* src/callint.c (Fcall_interactively):
* src/coding.c (decode_coding_object, encode_coding_object)
(code_convert_region, Ffind_operation_coding_system):
* src/comp.c (Fcomp_el_to_eln_rel_filename):
* src/conf_post.h (RE_TRANSLATE_P):
* src/data.c (Fkill_local_variable, Fash, expt_integer):
* src/dired.c (file_name_completion):
* src/dispnew.c (set_window_cursor_after_update, update_frame_1)
(Fframe_or_buffer_changed_p):
* src/doc.c (Fdocumentation, Fdocumentation_property)
(default_to_grave_quoting_style):
* src/editfns.c (Fconstrain_to_field, save_excursion_save)
(save_excursion_restore, Fngettext):
* src/eval.c (Fautoload, un_autoload, specbind):
* src/fileio.c (Fmake_temp_file_internal):
* src/fns.c (string_char_to_byte, string_byte_to_char)
(Fnthcdr, Fnreverse):
* src/indent.c (vmotion):
* src/inotify.c (add_watch):
* src/keyboard.c (command_loop_1, read_char)
(read_char_minibuf_menu_prompt):
* src/lread.c (oblookup):
* src/macfont.m (macfont_descriptor_entity, macfont_open):
* src/minibuf.c (Finnermost_minibuffer_p, Ftry_completion)
(Ftest_completion):
* src/nsfns.m (ns_set_icon_name):
* src/pdumper.c (dump_queue_dequeue):
* src/pgtkfns.c (pgtk_set_icon_type, pgtk_set_icon_name):
* src/process.c (Faccept_process_output):
* src/textprop.c (set_text_properties):
* src/w32fns.c (w32_set_icon_type, w32_set_icon_name):
* src/w32select.c (validate_coding_system):
* src/window.c (decode_next_window_args, window_loop)
(save_window_save):
* src/xdisp.c (wset_redisplay):
* src/xfaces.c (Fx_family_fonts, resolve_face_name)
(gui_supports_face_attributes_p):
* src/xfns.c (x_set_icon_type, x_set_icon_name):
* src/xselect.c (clean_local_selection_data):
Use BASE_EQ instead of EQ where it is obvious that neither argument
can be a symbol with properties or at least one argument is a
non-symbol.