bug#49789: 28.0.50; svg file is not displayed when opening (--with-x-toolkit=athena)

[Eli Zaretskii <eliz@gnu.org>]

> From: Uwe Brauer <oub@mat.ucm.es>
> Date: Sat, 31 Jul 2021 09:12:46 +0200
> 
> 
> With the configure option specification below, starting emacs -Q and trying to opening a svg file I see
> 
> 
> ,----
> | <?xml version="1.0" encoding="UTF-8" standalone="no"?>
> | <svg xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns="http://www.w3.org/2000/svg" xmlns:cc="http://creativecommons.org/ns#" xmlns:dc="http://purl.org/dc/elements/1.1/" enable-background="new 0 0 163 30" xml:space="preserve" height="30" viewBox="0 0 140 30" width="140" version="1.1" y="0px" x="0px">
> `----
> 
> I think this is a bug either in the toolkit option or in the
> documentation, that is it should point out that svg files are not
> opened.

I think it's neither, see below.

> However, I file to see why it should not open these files and
> display them.  I am on Ubuntu 16.04 and the official emacs version is
> 26, that emacs is able to open and display the svg file.

According to this:

> Configured features:
> ACL CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GPM GSETTINGS HARFBUZZ JPEG
> LCMS2 LIBOTF LIBSELINUX LIBXML2 M17N_FLT MODULES NOTIFY INOTIFY PDUMPER
> PNG SECCOMP SOUND THREADS TIFF TOOLKIT_SCROLL_BARS X11 XAW3D XDBE XIM
> XPM LUCID ZLIB

your build was not linked against the librsvg library (the RSVG
feature is not in the list), so it simply doesn't support display of
SVG images.