gnu: enchant: Update to 2.2.3.

* gnu/packages/enchant.scm (enchant): Update to 2.2.3.
[arguments]: Add "--enable-relocatable" to #:configure-flags.
[native-inputs]: Add UNITTEST-CPP.
(enchant-1.6): New public variable.
* gnu/packages/fcitx.scm (fcitx)[inputs]: Change ENCHANT to ENCHANT-1.6.
* gnu/packages/gnome.scm (gspell): Likewise.
* gnu/packages/mate.scm (pluma): Likewise.
* gnu/packages/gtk.scm (gtkspell3)[propagated-inputs]: Likewise.
[inputs]: Remove duplicate ENCHANT.

gnu/packages/fcitx.scm

@@ -75,7 +75,7 @@
        ("pkg-config" ,pkg-config)))
     (inputs
      `(("dbus"             ,dbus)
-       ("enchant"          ,enchant)
+       ("enchant"          ,enchant-1.6)
        ("gettext"          ,gettext-minimal)
        ("gtk2"             ,gtk+-2)
        ("gtk3"             ,gtk+)