* doc/emacs/search.texi (Regexp Backslash): Change xref from
"(elisp) Syntax Tables" to "(elisp) Syntax Class Table".

* doc/lispref/display.texi (Other Display Specs): Change xref from
"Images" to "Image Descriptors".

(bug#38519)

* doc/misc/semantic.texi (Parser code, Tag handling)
(Semanticdb Internals, Analyzer Internals, Tools): Fix file
names according to what was actually imported from the
original CEDET.  (Bug#38451)

* doc/lispref/files.texi (Saving Buffers): Remove the
reference to the obsolete Fast Lock mode.  (Bug#37956)

* lisp/simple.el (default-font-height, default-font-width)
(default-line-height): Say in the doc strings that the default
face these functions use is for the currently selected frame.

* doc/lispref/display.texi (Attribute Functions)
(Low-Level Font): Document more clearly the dependence of the
results of 'face-font', 'default-font-width', and
'default-font-height' on the frame's definition of the default
face.

* lisp/simple.el (minibuffer-history-values): New function, should be
used to access the minibuffer input history variable when the
minibuffer might be active.  If the variable is buffer-local, the
previous buffer's value will be used.
(goto-history-element): Use the new function to access the minibuffer
history.
(minibuffer-history-isearch-wrap): Use the new function to access the
minibuffer history.
* src/minibuf.c (read_minibuf): Switch to previous buffer temporarily
before updating history list (Bug#38317).
(read-from-minibuffer): Extend documentation to mention that the
result of using the command will be added to the history list by
default.
* doc/lispref/minibuf.texi (Minibuffer History): Mention the
possibility of using a buffer-local variable as history.
* etc/NEWS: Announce changes.

(tab-bar--tab): Use float-time instead of integer.
This improves correct detection of recent tabs switched within 1 sec.
(tab-bar--current-tab, tab-bar--current-tab-index)
(tab-bar--tab-index, tab-bar--tab-index-by-name)
(tab-bar--tab-index-recent): Add optional arg FRAME.
(tab-bar-move-tab-to-frame): Add with-selected-frame for tab-bar-close-tab.
(tab-bar--reusable-frames): New function.
(tab-bar-get-buffer-tab): Add index to the found tab.
(display-buffer-in-tab): Use `tab-name' entry instead of `name'.
Add `reusable-frames' entry.  (bug#38354)

As described in the new comment added to emacs-module.c, using GMP
directly in the module interface has significant downsides: it couples
the module interface directly to the implementation and requires
module authors to link their module against the same GMP library as
Emacs itself, which is often difficult and an unnecessary burden.  By
picking a representation for the magnitude that often matches the one
used by GMP, we can avoid overhead when converting from and to GMP in
most cases.

Loading the test module in test/data/emacs-module and evaluating

(dotimes (_ 10000)
  (mod-test-double (* 2 most-negative-fixnum)))

under Callgrind shows that on my (GNU/Linux) machine Emacs only spends
10% of the CPU time of mod-test-double in mpz_import and mpz_export
combined, even though that function does little else.  (By contrast,
30% is spent in allocate_pseudovector.)

* src/emacs-module.h.in: Don't check EMACS_MODULE_GMP.  Don't include
gmp.h.  Remove emacs_mpz structure.  Instead, define type alias
emacs_limb_t and macro EMACS_LIMB_MAX.

* src/module-env-27.h: Change interface of extract_big_integer and
make_big_integer to take a sign-magnitude representation instead of
mpz_t.

* src/emacs-module.c: Don't check EMACS_MODULE_GMP or
EMACS_MODULE_HAVE_MPZ_T.  Add a comment about the chosen
implementation.
(module_extract_big_integer, module_make_big_integer): Reimplement
without using mpz_t in the interface.

* doc/lispref/internals.texi (Module Values): Adapt function
documentation and example.  Stop mentioning GMP and EMACS_MODULE_GMP.

* test/data/emacs-module/mod-test.c: Don't define EMACS_MODULE_GMP or
EMACS_MODULE_HAVE_MPZ_T.
(memory_full, extract_big_integer, make_big_integer): New helper
functions, identical to example in the Info documentation.
(Fmod_test_nanoseconds, Fmod_test_double): Adapt to new interface.

(tab-bar-tabs, tab-bar--tab): Add optional arg FRAME.
(tab-bar-get-buffer-tab): Funcall tab-bar-tabs-function with arg FRAME
instead of using with-selected-frame.

* doc/misc/gnus.texi (Tabbed Interface): New node.  (bug#37998)

* doc/emacs/maintaining.texi (Switching Branches)
(Pulling / Pushing, Merging): Fix markup of shell commands.

* lisp/vc/vc-hg.el (vc-hg-merge-branch): Prompt for revision to merge.
(vc-hg-revision-table): Use branches, tags and bookmarks as competion
candidates.

* etc/NEWS: Mention changes of vc-hg.el

* doc/emacs/maintaining.texi (Switching Branches): Mention 'hg update'
command.
(Merging): Mention 'hg merge' command.

This fixes bug#22860

* doc/emacs/killing.texi (Other Kill Commands): Document
'zap-up-to-char'.

* lisp/simple.el (zap-to-char): Mention 'zap-up-to-char' in
the doc string.  (Bug#38392)

* doc/emacs/maintaining.texi (VC Change Log): Add missing
index entries.

* lisp/vc/vc.el (vc-print-root-log): Improve the wording of
the doc string and of the prompt for the root directory.

* etc/NEWS: Improve and expand the wording of the changes in
'C-x v L'.

* doc/emacs/maintaining.texi (VC Change Log): Improve and
clarify wording of the 'C-x v L' description.

Add some hints to the message for byte compiler free & unused variable
warnings, and 'void-variable' errors where the variable has confusable
quote characters in it.
* lisp/help.el (uni-confusables), uni-confusables-regexp): New
constants.
(help-command-error-confusable-suggestions): New function, added to
`command-error-function'.
(help-uni-confusable-suggestions): New function.
* lisp/emacs-lisp/bytecomp.el (byte-compile-variable-ref):
* lisp/emacs-lisp/cconv.el (cconv--analyze-use): Use it.

* lisp/emacs-lisp/lisp-mode.el
(lisp--match-confusable-symbol-character): New function.
(lisp-fdefs): Use it to fontify confusable characters with
font-lock-warning-face when they occur in symbol names.
* doc/lispref/modes.texi (Faces for Font Lock):
* doc/lispref/objects.texi (Basic Char Syntax): Recommend backslash
escaping of confusable characters, and mention new fontification.
* etc/NEWS: Announce the new fontification behavior.
* test/lisp/emacs-lisp/lisp-mode-tests.el (lisp-fontify-confusables):
New test.

* doc/emacs/maintaining.texi (VC Change Log): Explain the numeric prefix arg
of 'C-x v L' (vc-print-root-log).

* lisp/vc/vc-git.el (vc-git-print-log): Add command line option "-p"
when vc-log-view-type is 'with-diff'.
(vc-git-log-view-mode): Use long style when vc-log-view-type is 'with-diff'.

* lisp/vc/vc.el (vc-print-log-internal): Add optional arg 'type'.
(vc-log-internal-common): Use 'region-history-mode' when type is
'with-diff' and backend supports 'region-history-mode'.
(vc-print-root-log): Add optional arg 'revision'.  In interactive spec
read a revision when current-prefix-arg is 1.  Use current-prefix-arg
"as is" when it is a number.  Show revision in long style with diff
when limit is 1 and revision is non-nil.

Make it possible to select a rectangular region using the mouse.
The standard binding is C-M-mouse-1.

* lisp/mouse.el (mouse-scroll-subr): Add ADJUST argument.
(mouse-drag-region-rectangle): New.
* lisp/rect.el (rectangle--reset-point-crutches): New.
(rectangle--reset-crutches): Use 'rectangle--reset-point-crutches'.
* src/xdisp.c (remember_mouse_glyph, syms_of_xdisp):
Add 'mouse-fine-grained-tracking'.
* doc/lispref/commands.texi (Motion Events):
Document 'mouse-fine-grained-tracking'.
* doc/emacs/frames.texi (Mouse Commands):
* doc/emacs/killing.texi (Rectangles):
* etc/NEWS: Document rectangular selection with the mouse.

* doc/misc/eieio.texi (Predicates): Update the documentation of
eieio-class-name to say what it really returns (bug#38365).

For the ns-KEY-modifier and ns-right-KEY-modifier variables, KEY
being 'control', 'command', 'alternate' and 'function', allow
values on the form (:ordinary SYMBOL :function :SYMBOL :mouse SYMBOL),
so that the key can be used for different modifiers (or none) in
different contexts.  This is particularly useful for using the macOS
Option key for extended character entry while still using it as an
Emacs modifier for function keys and mouse clicks.

* src/nsterm.m (mod_of_kind, right_mod, nil_or_none): Helper functions.
(EV_MODIFIERS2): Add KIND argument.
(EV_MODIFIERS): Adapt call to EV_MODIFIERS2.
(ns_get_shifted_character): Use correct event kind for modifiers.
(ns-alternate-modifier, ns-right-alternate-modifier)
(ns-command-modifier, ns-right-command-modifier)
(ns-control-modifier, ns-right-control-modifier)
(ns-function-modifier): Rewrite doc strings for new data format.
(QCordinary, QCfunction, QCmouse): Define symbols.
* lisp/cus-start.el: Conform to new data types.
* doc/emacs/macos.texi (Mac / GNUstep Basics)
(Mac / GNUstep Customization): Improved documentation.
* etc/NEWS: Mention the change.

* doc/lispref/display.texi (Displaying Messages): Explain the
behavior of using minibuffer-message if the minibuffer is active.

* src/editfns.c (Fmessage_in_echo_area): New function with body
copied from Fmessage.
(Fmessage): Call minibuffer-message in the active minibuffer,
otherwise call Fmessage_in_echo_area.
(message-in-echo-area): New variable.

* lisp/isearch.el (isearch--momentary-message, isearch-message):
* lisp/minibuffer.el (minibuffer-message, minibuffer-completion-help):
Use 'message-in-echo-area' instead of 'message' where necessary.

* lisp/autorevert.el (auto-revert-handler):
* lisp/man.el (Man-bgproc-sentinel):
* lisp/subr.el (do-after-load-evaluation):
Revert recent changes that replaced 'message' with 'minibuffer-message'.
This is not needed anymore since 'message' uses 'minibuffer-message'
in the active minibuffer.

* lisp/window.el (switch-to-visible-buffer): Declare obsolete.
(switch-to-prev-buffer-skip): New option.
(switch-to-prev-buffer, switch-to-next-buffer): Obey
'switch-to-prev-buffer-skip'.
* doc/lispref/windows.texi (Window History): Remove
description of 'switch-to-visible-buffer'.  Describe new
option 'switch-to-prev-buffer-skip'
* etc/NEWS: Mention switch from 'switch-to-visible-buffer' to
'switch-to-prev-buffer-skip'.

Bug#38218

* src/process.c (Fnetwork_interface_list): Extend argument list to
allow requesting full network info and/or IPv4/IPv6 info.
(network_interface_list) [HAVE_GETIFADDRS]: Use getifaddrs to retrieve
interface IP addresses.

* src/process.h: Update prototype of network_interface_list.

* src/w32.c (g_b_init_get_adapters_addresses): New init flag.
(globals_of_w32): Initialize it.
(GetAdaptersAddresses_Proc): New function typedef.
(get_adapters_addresses): New wrapper function.
(init_winsock): Load htonl and ntohl.
(sys_htonl, sys_ntohl): New wrapper functions.
(network_interface_list): Implement in terms of
get_adapters_addresses.

* nt/inc/sys/socket.h: Add sys_htonl and sys_ntohl prototypes.

* etc/NEWS: Announce IPv4/IPv6 changes in network-interface-list.

* doc/lispref/processes.texi (Misc Network): Document updated arglist
and return values for network-interface-list.

* doc/misc/eieio.texi (Predicates): Remove documentation of
same-class-fast-p, which was removed some years back (bug#38362).

* lisp/net/network-stream.el (network-stream-use-client-certificates):
Default to nil.
(open-network-stream): Adapt description to new default of
network-stream-use-client-certificates.

* etc/NEWS: network-stream-use-client-certificates defaults to nil
now.

* doc/lispref/processes.texi (Network): Flip
network-stream-use-client-certificates description.

* doc/misc/auth.texi (Help for users): Mention
network-stream-use-client-certificates.

* lisp/simple.el (what-cursor-show-names): New defcustom, default nil.
(what-cursor-position): Show character names if what-cursor-show-names
is non-nil.

* doc/emacs/basic.texi (Position Info): Add what-cursor-show-names
description.

* etc/NEWS: Announce what-cursor-show-names.

* doc/emacs/commands.texi (User Input): Add index entry for
the Alt key serving as Meta.
* doc/emacs/custom.texi (Modifier Keys): Add index entries for
Alt, Super, and Hyper modifier keys.  (Bug#38315)

* doc/lispref/objects.texi (Special Read Syntax): Fix wording
of the last change: don't document #' twice.  (Bug#38278)

* lisp/vc/vc-hg.el (vc-hg-region-history)
(vc-hg-region-history-font-lock, vc-hg-region-history-mode):
New functions.
(vc-hg-region-history-mode-map)
(vc-hg--log-view-long-font-lock-keywords)
(vc-hg-region-history-font-lock-keywords): New variables.
* lisp/vc/vc-git.el (vc-git-region-history): Update commentary.

* doc/emacs/maintaining.texi (VC Change Log): Add
'vc-region-history' to the table at beginning of node.  Update
the VCSes that support 'vc-region-history'.

* etc/NEWS: Mention the new feature of vc-hg.el.

* doc/lispref/objects.texi (Special Read Syntax): Add an xref for
the #' (bug#38278).

* doc/lispref/objects.texi (Special Read Syntax): Document the #'
syntax (bug#38278).

* doc/misc/tramp.texi (Default User): Fix typo.
(Cleanup remote connections): Adapt arguments of
`tramp-cleanup-connection'.
(Renaming remote files): New node.
(Frequently Asked Questions): New item "How to save files when a
remote host isn't reachable anymore?".

* etc/NEWS: Add `tramp-rename-files' and `tramp-rename-these-files'.

* lisp/net/tramp-cmds.el (tramp-default-rename-alist)
(tramp-confirm-rename-file-names): New defcustoms.
(tramp-rename-read-file-name-dir)
(tramp-rename-read-file-name-init): New defsubsts.
(tramp-default-rename-file, tramp-rename-files)
(tramp-rename-these-files): New defuns.

* lisp/net/tramp-integration.el (ido, ivy): Integrate with them.

* doc/misc/gnus.texi (Foreign Groups, Web Searches, What is nnir?):
(Setting up nnir, Associating Engines, The imap Engine):
(Customizations): Remove references to gmane web search.

* lisp/dired-aux.el (dired-dwim-target-next): Add arg ALL-FRAMES.
(dired-dwim-target-next-visible): New function.

* doc/emacs/dired.texi (Operating on Files): Describe function value
of dired-dwim-target.  (Bug#35385)

* doc/lispref/edebug.texi (Instrumenting): Reword the description
of the edebug-remove-instrumentation command.

* doc/lispref/functions.texi (Function Documentation): Improve
indexing (bug#38158).

* doc/lispref/variables.texi (Watching Variables): Clarify the
documentation of 'add-variable-watcher' and fix markup.

* src/data.c (Fadd_variable_watcher): Clarify the doc string.
(Bug#38205)

* doc/lispref/minibuf.texi (Multiple Queries): Move the
reference to 'read-char-from-minibuffer' from here...
* doc/lispref/commands.texi (Reading One Event): ...to here.
Fix the wording of the description of
'read-char-from-minibuffer'.

* lisp/dired.el (dired-dwim-target): Add choices
dired-dwim-target-next and dired-dwim-target-recent.

* lisp/dired-aux.el (dired-dwim-target-next)
(dired-dwim-target-recent): New functions.
(dired-dwim-target-directories): Call either of them.

* doc/emacs/dired.texi (Operating on Files): Mention new
preferences in dired-dwim-target.