bug#42425: 26.3.50; Compilation warnings when compiling eldoc.el under Emacs 26.3

[Philipp Stephani]

eldoc is now a separate package that claims to support Emacs 26.3.
However, compiling eldoc.el results in a few warnings:

emacs -Q -batch -l bytecomp -f batch-byte-compile eldoc.el

In eldoc--eval-expression-setup:
eldoc.el:236:9:Warning: assignment to free variable
    ‘eldoc-documentation-strategy’

In eldoc--supported-p:
eldoc.el:615:19:Warning: reference to free variable
    ‘eldoc-documentation-strategy’

In eldoc--invoke-strategy:
eldoc.el:732:28:Warning: reference to free variable
    ‘eldoc-documentation-strategy’

In end of data:
eldoc.el:804:1:Warning: the following functions are not known to be defined:
    elisp-eldoc-var-docstring, elisp-eldoc-funcall

1. Probably the definition of `eldoc-documentation-strategy' needs to be
   moved before its first use.

2. Probably eldoc should protect against newer Elisp functions being not
   yet available, as calling such functions will likely result in errors
   at runtime.


In GNU Emacs 26.3.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.14)
 of 2020-06-29
Repository revision: 7497ee44b471f69ce59d131a6dece261e871534f
Windowing system distributor 'The X.Org Foundation', version 11.0.12008000
System Description:     Debian GNU/Linux rodete

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
Eager macro-expansion failure: (error "Unknown seq pattern: (seq 3 (pred 
(lambda (c) (and (characterp c) (= (aref (symbol-name (category c)) 0) 76)))))")

Configured using:
 'configure --enable-checking --enable-gtk-deprecation-warnings
 --enable-gcc-warnings=warn-only --with-modules --without-pop
 --with-mailutils --enable-check-lisp-object-type 'CFLAGS=-ggdb3 -O0''

Configured features:
XPM JPEG TIFF GIF PNG SOUND DBUS GSETTINGS GLIB NOTIFY LIBSELINUX GNUTLS
FREETYPE XFT ZLIB TOOLKIT_SCROLL_BARS GTK3 X11 XDBE XIM MODULES THREADS

Important settings:
  value of $LANG: en_US.utf8
  value of $XMODIFIERS: @im=ibus
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message rmc puny seq dired
dired-loaddefs format-spec rfc822 mml easymenu mml-sec epa epg
epg-config gnus-util rmail rmail-loaddefs mm-decode mm-bodies mm-encode
mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047
rfc2045 ietf-drums mm-util mail-prsvr mail-utils phst skeleton derived
edmacro kmacro pcase ffap thingatpt url url-proxy url-privacy url-expand
url-methods url-history url-cookie url-domsuf url-util url-parse
auth-source cl-seq eieio byte-opt bytecomp byte-compile cconv eieio-core
cl-macs gv eieio-loaddefs password-cache url-vars mailcap subr-x rx
gnutls dbus xml compile comint ansi-color ring cl-loaddefs cl-lib
elec-pair time-date mule-util tooltip eldoc electric uniquify ediff-hook
vc-hooks lisp-float-type mwheel term/x-win x-win term/common-win x-dnd
tool-bar dnd fontset image regexp-opt fringe tabulated-list replace
newcomment text-mode elisp-mode lisp-mode prog-mode register page
menu-bar rfn-eshadow isearch timer select scroll-bar mouse jit-lock
font-lock syntax facemenu font-core term/tty-colors frame cl-generic
cham georgian utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao
korean japanese eucjp-ms cp51932 hebrew greek romanian slovak czech
european ethiopic indian cyrillic chinese composite charscript charprop
case-table epa-hook jka-cmpr-hook help simple abbrev obarray minibuffer
cl-preloaded nadvice loaddefs button faces cus-face macroexp files
text-properties overlay sha1 md5 base64 format env code-pages mule
custom widget hashtable-print-readable backquote threads dbusbind
inotify dynamic-setting system-font-setting font-render-setting
move-toolbar gtk x-toolkit x multi-tty make-network-process emacs)

Memory information:
((conses 16 117319 5856)
 (symbols 48 22667 1)
 (miscs 40 42 114)
 (strings 32 35666 1100)
 (string-bytes 1 970671)
 (vectors 16 17078)
 (vector-slots 8 536734 16344)
 (floats 8 54 68)
 (intervals 56 221 0)
 (buffers 992 12))

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