gnu: guile-rsvg: Update to commit 05c6a2fd.

* gnu/packages/gtk.scm (guile-rsvg): Update to commit 05c6a2fd.
[source](url): Change to gitlab.com.
(snippet): Use @GUILE_EFFECTIVE_VERSION@ instead of "2.0".
* gnu/packages/patches/guile-rsvg-pkgconfig.patch: Use
"$GUILE_EFFECTIVE_VERSION" instead of "2.0".

gnu/packages/gtk.scm

@@ -813,22 +813,28 @@ exceptions, macros, and a dynamic programming environment.")
     (license license:lgpl3+)))
 
 (define-public guile-rsvg
+  ;; Use a recent snapshot that supports Guile 2.2 and beyond.
+  (let ((commit "05c6a2fd67e4fea1a7c3ff776729dc931bae6678")
+        (revision "0"))
     (package
       (name "guile-rsvg")
-    (version "2.18.1")
+      (version (string-append "2.18.1-" revision "."
+                              (string-take commit 7)))
       (source (origin
                 (method url-fetch)
-              (uri (string-append "http://wingolog.org/pub/guile-rsvg/"
-                                  name "-" version ".tar.gz"))
+                (uri (string-append "https://gitlab.com/wingo/guile-rsvg/"
+                                    "repository/archive.tar.gz?ref="
+                                    commit))
                 (sha256
                  (base32
-                "136f236iw3yrrz6pkkp1ma9c5mrs5icqha6pnawinqpk892r3jh7"))
+                  "0vdzjx8l5nc4y2xjqs0g1rqn1zrwfsm30brh5gz00r1x41a2pvv2"))
                 (patches (search-patches "guile-rsvg-pkgconfig.patch"))
                 (modules '((guix build utils)))
                 (snippet
                  '(substitute* (find-files "." "Makefile\\.am")
                     (("/share/guile/site")
-                   "/share/guile/site/2.0")))))
+                     "/share/guile/site/@GUILE_EFFECTIVE_VERSION@")))
+                (file-name (string-append name "-" version ".tar.gz"))))
       (build-system gnu-build-system)
       (arguments
        `(#:phases (modify-phases %standard-phases
@@ -849,7 +855,7 @@ exceptions, macros, and a dynamic programming environment.")
        "Guile-RSVG wraps the RSVG library for Guile, allowing you to render SVG
 images onto Cairo surfaces.")
       (home-page "http://wingolog.org/projects/guile-rsvg/")
-    (license license:lgpl2.1+)))
+      (license license:lgpl2.1+))))
 
 (define-public guile-present
   (package

gnu/packages/patches/guile-rsvg-pkgconfig.patch

@@ -9,7 +9,7 @@ and LDFLAGS for Guile would not be captured.
  
 +dnl The above macro fails to set the 'GUILE_CFLAGS' and 'GUILE_LIBS'
 +dnl substitution variables, hence this line.
-+PKG_CHECK_MODULES(GUILE, guile-2.0)
++PKG_CHECK_MODULES(GUILE, guile-$GUILE_EFFECTIVE_VERSION)
 +
  PKG_CHECK_MODULES(GUILE_CAIRO, guile-cairo >= 1.4.0)
  AC_SUBST(GUILE_CAIRO_LIBS)