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.

86b49d5865 ; * etc/NEWS: Announce changes in 'desktop-kill'.  (Bug#55...
d5ccf2621a ; Fix last change
f1c1fd7184 Improve documentation of mail-user-agent.
b05d1e9b98 ; * lisp/desktop.el: Update the commentary.  (Bug#55560)
139bfa1a08 More fixes in abbrev.el doc strings
d80dea6036 Add note about Tramp completion to completion-styles doc s...
9e7c0cf57d Remove mention of removed nnimap-nov-is-evil variable
90aae0bca2 Improve documentation strings and prompts in abbrev.el
dfa3e6f424 Restore the Fselect_window call in gui_consider_frame_title.
de35e9728f Advise against settings in the MS-Windows system registry
3ffa3d3403 ; Minor addition to make-tarball.txt
7dc026f9ea Fix kmacro-keymap binding after previous change
4f0fd54bc4 Add glossary entries for "interactively"
af1c05a3c4 Fix the name of a kmacro command.

# Conflicts:
#	etc/NEWS
#	lisp/abbrev.el

* doc/lispref/text.texi (Yanking): Adjust.
* lisp/simple.el (yank-transform-functions): Make into defvar
because it's not that useful as a user option.

* lisp/eshell/esh-cmd.el (eshell-execute-pipeline): Use 'make-symbol'
for headproc and tailproc.
(eshell-do-pipelines, eshell-do-pipelines-synchronously): Adapt to the
above.

* test/lisp/eshell/eshell-tests.el (eshell-test/pipe-subcommand)
(eshell-test/pipe-subcommand-with-pipe): New test.

* doc/misc/eshell.texi (Bugs and ideas): Remove item about piping to
process from loop; this commit fixes it (bug#55590).

* doc/misc/tramp.texi (Archive file names):
* lisp/net/tramp-archive.el (tramp-archive-suffixes): Add ".epub".

* lisp/minibuffer.el (completion-in-region-mode-map): Add keybindings M-<up>
for minibuffer-previous-completion, M-<down> for minibuffer-next-completion,
M-RET for minibuffer-choose-completion.
(completion-in-region-mode): Set buffer-local
'minibuffer-completion-auto-choose' to nil.
(minibuffer-next-completion): Get the value of
'minibuffer-completion-auto-choose' from the minibuffer.
(minibuffer-previous-completion): Simplify by delegating to
'minibuffer-next-completion'.

* doc/emacs/programs.texi (Symbol Completion): Add description of keys
M-down, M-up, M-RET.

https://lists.gnu.org/archive/html/emacs-devel/2022-05/msg00916.html

* doc/emacs/sending.texi (Mail Methods): Fix indexing and markup.
(Bug#55569)

* doc/emacs/sending.texi (Mail Methods):
* lisp/simple.el (mail-user-agent): Mention additional options
of non-bundled MUA.  (Bug#5569)

* doc/misc/gnus.texi (Slow/Expensive Connection): Remove mention
of removed nnimap-nov-is-evil variable (bug#55556).