gnu: fontconfig: Add replacement with font-dejavu instead of gs-fonts.

This fixes <https://bugs.gnu.org/41282>, <https://bugs.gnu.org/41241>, and
<https://bugs.gnu.org/41344>.
Reported by Pierre Neidhardt, W Knight, Alexandros Theodotou, and others.

* gnu/packages/fontutils.scm (fontconfig)[replacement]: New field.
(fontconfig/font-dejavu): New variable.

gnu/packages/fontutils.scm

@@ -37,6 +37,7 @@
   #:use-module (gnu packages perl)
   #:use-module (gnu packages pkg-config)
   #:use-module (gnu packages autotools)
+  #:use-module (gnu packages fonts)
   #:use-module (gnu packages gettext)
   #:use-module (gnu packages python)
   #:use-module (gnu packages python-xyz)
@@ -292,6 +293,12 @@ fonts to/from the WOFF2 format.")
 (define-public fontconfig
   (package
    (name "fontconfig")
+
+   ;; This replacement is not security-related, but works around the fact
+   ;; that gs-fonts are not recognized by newer versions of Pango, causing
+   ;; many applications to fail to find fonts otherwise.
+   (replacement fontconfig/font-dejavu)
+
    (version "2.13.1")
    (source (origin
             (method url-fetch)
@@ -348,6 +355,13 @@ high quality, anti-aliased and subpixel rendered text on a display.")
                        "See COPYING in the distribution."))
    (home-page "https://www.freedesktop.org/wiki/Software/fontconfig")))
 
+(define fontconfig/font-dejavu
+  (package
+    (inherit fontconfig)
+    (inputs
+     ;; XXX: Reuse the name to avoid having to override the configure flags.
+     `(("gs-fonts" ,font-dejavu)))))
+
 (define-public t1lib
   (package
    (name "t1lib")