bug#55719: 29.0.50; various bindat strz bugs

[Richard Hansen]

There are a number of bugs with strz packing and unpacking in the bindat
package:

(require 'bindat)
(require 'ert)
(let ((s (bindat-type :pack-var v (x strz :pack-val v) :unpack-val x)))
  ;; Bug: length doesn't count the null terminator.
  (ert-deftest t1 () (should (equal (bindat-length s "x") 2)))
  ;; Bug: pack doesn't include the null terminator.
  (ert-deftest t2 () (should (equal (bindat-pack s "x") "\170\0")))
  ;; Bug: unpack throws (wrong-type-argument number-or-marker-p nil)
  (ert-deftest t3 () (should (equal (bindat-unpack s "\170\0") "x"))))
(let ((s (bindat-type :pack-var v (x strz 2 :pack-val v) :unpack-val x)))
  ;; Bug: pack doesn't always include the null terminator.
  (ert-deftest t4 () (should (equal (bindat-pack s "xx") "\170\0"))))
(let ((s '((x strz 2))))
  ;; Bug: pack doesn't always include the null terminator.
  (ert-deftest t5 () (should (equal (bindat-pack s '((x . "xx"))) "\170\0"))))

In addition to the above issues, legacy-style specs with no strz length,
such as '((x strz)), do not work. But I suspect length only became
optional when `bindat-type' was introduced, so that's probably not an
issue.

In GNU Emacs 29.0.50 (build 2, x86_64-pc-linux-gnu, GTK+ Version 3.24.20, cairo 
version 1.16.0)
 of 2022-05-29 built on sprinkles
Repository revision: 7f7acf395697e4cfa470cfa2993b70c2308e95c1
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12013000
System Description: Ubuntu 20.04.4 LTS

Configured using:
 'configure --build=x86_64-linux-gnu --prefix=/usr
 '--includedir=${prefix}/include' '--mandir=${prefix}/share/man'
 '--infodir=${prefix}/share/info' --sysconfdir=/etc --localstatedir=/var
 --disable-option-checking --disable-silent-rules
 '--libdir=${prefix}/lib/x86_64-linux-gnu'
 '--libexecdir=${prefix}/lib/x86_64-linux-gnu' --disable-maintainer-mode
 --disable-dependency-tracking --prefix=/usr --sharedstatedir=/var/lib
 --with-modules=yes --with-x=yes --with-x-toolkit=gtk3
 --with-xwidgets=yes --without-pgtk'

Configured features:
ACL CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GPM GSETTINGS HARFBUZZ JPEG
JSON LCMS2 LIBOTF LIBSELINUX LIBSYSTEMD LIBXML2 M17N_FLT MODULES NOTIFY
INOTIFY PDUMPER PNG RSVG SECCOMP SOUND SQLITE3 THREADS TIFF
TOOLKIT_SCROLL_BARS X11 XDBE XIM XINPUT2 XPM XWIDGETS GTK3 ZLIB

Important settings:
  value of $LC_MONETARY: en_US.UTF-8
  value of $LC_NUMERIC: en_US.UTF-8
  value of $LC_TIME: root.UTF-8
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  eldoc-mode: t
  show-paren-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
  line-number-mode: t
  indent-tabs-mode: t
  transient-mark-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message mailcap yank-media rmc puny
dired dired-loaddefs rfc822 mml mml-sec epa derived epg rfc6068
epg-config gnus-util text-property-search mm-decode mm-bodies mm-encode
mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047
rfc2045 ietf-drums mm-util mail-prsvr mail-utils ffap thingatpt
url-parse auth-source eieio eieio-core eieio-loaddefs password-cache
json url-vars help-fns radix-tree cl-print cl-extra ert map seq pp ewoc
debug backtrace help-mode find-func bindat byte-opt bytecomp
byte-compile cconv pcase cl-seq cl-macs gv time-date subr-x cl-loaddefs
cl-lib iso-transl tooltip eldoc paren electric uniquify ediff-hook
vc-hooks lisp-float-type elisp-mode 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 lisp-mode prog-mode register
page tab-bar menu-bar rfn-eshadow isearch easymenu timer select
scroll-bar mouse jit-lock font-lock syntax font-core term/tty-colors
frame minibuffer nadvice simple cl-generic indonesian philippine 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 emoji-zwj charscript
charprop case-table epa-hook jka-cmpr-hook help abbrev obarray oclosure
cl-preloaded button loaddefs faces cus-face macroexp files window
text-properties overlay sha1 md5 base64 format env code-pages mule
custom widget keymap hashtable-print-readable backquote threads
xwidget-internal dbusbind inotify lcms2 dynamic-setting
system-font-setting font-render-setting cairo move-toolbar gtk x-toolkit
xinput2 x multi-tty make-network-process emacs)

Memory information:
((conses 16 74917 10902)
 (symbols 48 8201 0)
 (strings 32 23138 2251)
 (string-bytes 1 732663)
 (vectors 16 16128)
 (vector-slots 8 211715 13201)
 (floats 8 98 309)
 (intervals 56 475 0)
 (buffers 992 14))