bug#70713: 29.3; Official Windows build - RSVG is either using an outdated version of the library or SVG support is not compiled correctly

[Dewu <dewu@tfwno.gf>]

SVG (RSVG) support appears broken on the official Windows builds of GNU
Emacs.
This appears most prominently in osm (osm.el) by minad, available both 
on GNU
ELPA and MELPA, which uses SVG to display map tiles and location pins in 
the
buffer.
The tiles with pins under them appear to be blank, regardless of zoom
levels or tile set used.

The issue had been known to the developer of osm.el, as it was 
previously
reported on both Windows and macOS:
- https://github.com/minad/osm/issues/23
- https://github.com/minad/osm/issues/40
The conclusion was that both builds of Emacs lacked proper SVG support 
to display the tiles correctly.

This does not happen on any versions of Emacs built for GNU/Linux
available in official repositories or Flatpak.

I suspect that Emacs for Windows is either not built correctly with RSVG 
support, or
the library it is built against is too old (librsvg-2-2.dll).
This does not happen in Emacs built by MSYS2 (mingw-w64-x86_64-emacs) 
which
appears to be using a newer version of librsvg
(mingw-w64-x86_64-librsvg 2.58.0-1)

To replicate:
- emacs -Q
- acquire osm (GitHub, ELPA, or MELPA)
- load it (manually, autoloads, use-package etc.)
- M-x osm RET
- navigate the map
- click on the map, add boomarks etc.
- map tiles with pins under them appears blank


In GNU Emacs 29.3 (build 2, x86_64-w64-mingw32) of 2024-03-24 built on
  AVALON
Windowing system distributor 'Microsoft Corp.', version 10.0.19045
System Description: Microsoft Windows 10 Pro (v10.0.2009.19045.4291)

Configured using:
  'configure --with-modules --without-dbus --with-native-compilation=aot
  --without-compress-install --with-sqlite3 --with-tree-sitter
  CFLAGS=-O2'

Configured features:
ACL GIF GMP GNUTLS HARFBUZZ JPEG JSON LCMS2 LIBXML2 MODULES NATIVE_COMP
NOTIFY W32NOTIFY PDUMPER PNG RSVG SOUND SQLITE3 THREADS TIFF
TOOLKIT_SCROLL_BARS TREE_SITTER WEBP XPM ZLIB

(NATIVE_COMP present but libgccjit not available)

Important settings:
   value of $LANG: PLK
   locale-coding-system: cp1250

Major mode: Osm

Minor modes in effect:
   tooltip-mode: t
   global-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
   buffer-read-only: 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 puny dired
dired-loaddefs rfc822 mml mml-sec epa derived epg rfc6068 epg-config
gnus-util time-date mm-decode mm-bodies mm-encode mail-parse rfc2231
mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums
mm-util mail-prsvr mail-utils mule-util format-spec url-util url-parse
auth-source cl-seq eieio eieio-core cl-macs password-cache json subr-x
map byte-opt gv bytecomp byte-compile url-vars osm dom bookmark
text-property-search pp compat compat-autoloads osm-autoloads thingatpt
cl-loaddefs cl-lib find-func rmc iso-transl tooltip cconv eldoc paren
electric uniquify ediff-hook vc-hooks lisp-float-type elisp-mode mwheel
dos-w32 ls-lisp disp-table term/w32-win w32-win w32-vars term/common-win
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 seq
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 theme-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
w32notify w32 lcms2 multi-tty make-network-process native-compile emacs)

Memory information:
((conses 16 78366 12110)
  (symbols 48 7186 0)
  (strings 32 23222 1764)
  (string-bytes 1 670931)
  (vectors 16 15482)
  (vector-slots 8 344174 16638)
  (floats 8 128 293)
  (intervals 56 420 1)
  (buffers 984 12))