gnu: font-gnu-freefont: Build with an older version of FontForge.

Fixes <https://bugs.gnu.org/40819>.
Reported by Jack Hill <jackhill@jackhill.us>.

* gnu/packages/fontutils.scm (fontforge-20190801): New public variable.
* gnu/packages/fonts.scm (font-gnu-freefont)[native-inputs]: Change from
inherited FontForge variant to FONTFORGE-20190801.

gnu/packages/fontutils.scm

@@ -60,7 +60,9 @@
   #:use-module (guix build-system cmake)
   #:use-module (guix build-system gnu)
   #:use-module (guix build-system python)
-  #:use-module (guix build-system meson))
+  #:use-module (guix build-system meson)
+  #:use-module (guix utils)
+  #:use-module (srfi srfi-1))
 
 (define-public freetype
   (package
@@ -640,6 +642,31 @@ generate bitmaps.")
    (license license:gpl3+)
    (home-page "https://fontforge.github.io")))
 
+;; This is the last version that supports Python 2, which is needed for
+;; GNU FreeFont.  Remove once no longer required.
+(define-public fontforge-20190801
+  (package
+    (inherit fontforge)
+    (version "20190801")
+    (source (origin
+              (method url-fetch)
+              (uri (string-append
+                    "https://github.com/fontforge/fontforge/releases/download/"
+                    version "/fontforge-" version ".tar.gz"))
+              (sha256
+               (base32 "0lh8yx01asbzxm6car5cfi64njh5p4lxc7iv8dldr5rwg357a86r"))))
+    (build-system gnu-build-system)
+    (arguments
+     (substitute-keyword-arguments (package-arguments fontforge)
+       ((#:configure-flags _)
+        ''())
+       ((#:phases phases)
+        `(modify-phases ,phases
+           (delete 'do-not-override-RPATH)))))
+    (inputs
+     `(("python" ,python-2)
+       ,@(alist-delete "python" (package-inputs fontforge))))))
+
 (define-public python2-ufolib
   (package
     (name "python2-ufolib")