gnu: Add xmonad-next and ghc-xmonad-contrib-next.

Fixes: <https://issues.guix.gnu.org/issue/52784>.

* gnu/packages/wm.scm (xmonad-next): New variable. Compared to xmonad: Update
to 0.17.0.
[inputs]: Add GHC-DATA-DEFAULT-CLASS, remove GHC-EXTENSIBLE-EXCEPTIONS,
GHC-DATA-DEFAULT, GHC-SEMIGROUPS, and GHC-UTF8-STRING.
[native-inputs]: Add GHC-QUICKCHECK and GHC-QUICKCHECK-CLASSES.
(ghc-xmonad-contrib-next): New variable. Compared to ghc-xmonad-contrib:
Update to 0.17.0.
[propagated-inputs]: Remove GHC-OLD-TIME, GHC-EXTENSIBLE-EXCEPTIONS,
GHC-SEMIGROUPS.
[native-inputs]: Add GHC-QUICKCHECK and GHC-HSPEC.
(xmonad): Inherit from xmonad-next.
(ghc-xmonad-contrib): Inherit from ghc-xmonad-contrib-next.
* gnu/packages/patches/xmonad-next-dynamic-linking.patch: New patch. Update of
xmonad-dynamic-linking.patch to apply to xmonad-next.
* gnu/local.mk: Add it.

Signed-off-by: Lars-Dominik Braun <lars@6xq.net>

gnu/packages/patches/xmonad-next-dynamic-linking.patch

@@ -0,0 +1,16 @@
+This patch is required for xmonad to make use of shared libraries.
+Without it, xmonad will not work since we do not (by default) use
+statically linked Haskell libraries.
+
+index 46a0939..5ad4f8f 100644
+--- a/src/XMonad/Core.hs
++++ b/src/XMonad/Core.hs
+@@ -664,6 +664,8 @@ compile dirs method =
+   where
+     ghcArgs = [ "--make"
+               , "xmonad.hs"
++              , "-dynamic"
++              , "-fPIC"
+               , "-i" -- only look in @lib@
+               , "-ilib"
+               , "-fforce-recomp"