gnu: cairomm-1.13: Fix build.

* gnu/packages/gtk.scm (cairomm-1.13)[build-system]: New field.
[arguments]: New field.
[propagated-inputs]: Replace libsigc++ with libsigc++-2.

Signed-off-by: Léo Le Bouter <lle-bout@zaclys.net>

gnu/packages/gtk.scm

@@ -1325,9 +1325,22 @@ (define-public cairomm-1.13
                        name "-" version ".tar.gz"))
        (sha256
         (base32 "1xlfl0fm5mgv53lr8xjv2kqsk3bz67qkk6qzvbrqmbvbvvbqp9wp"))))
+    (build-system glib-or-gtk-build-system)
+    (arguments
+     `(#:phases
+       (modify-phases %standard-phases
+         (add-after 'install 'move-doc
+           (lambda* (#:key outputs #:allow-other-keys)
+             (let* ((out (assoc-ref outputs "out"))
+                    (doc (assoc-ref outputs "doc")))
+               (mkdir-p (string-append doc "/share"))
+               (rename-file
+                (string-append out "/share/doc")
+                (string-append doc "/share/doc"))
+               #t))))))
     (propagated-inputs
-     `(("cairo" ,cairo)
-       ("sigc++" ,libsigc++)))))
+     `(("libsigc++" ,libsigc++-2)
+       ,@(package-propagated-inputs cairomm)))))
 
 (define-public pangomm
   (package