gnu: Add ghc-9.0.

* gnu/packages/haskell.scm (ghc-9.0): New variable.

Signed-off-by: Efraim Flashner <efraim@flashner.co.il>

gnu/packages/haskell.scm

@@ -1011,6 +1011,42 @@ interactive environment for the functional language Haskell.")
 
 (define-public ghc-8 ghc-8.10)
 
+(define-public ghc-9.0
+  (package
+    (inherit ghc-8.10)
+    (name "ghc-next")
+    (version "9.0.2")
+    (source (origin
+              (method url-fetch)
+              (uri (string-append "https://www.haskell.org/ghc/dist/" version
+                                  "/ghc-" version "-src.tar.xz"))
+              (sha256
+               (base32
+                "15wii8can2r3dcl6jjmd50h2jvn7rlmn05zb74d2scj6cfwl43hl"))))
+    (native-inputs
+     `(;; GHC 9.0.2 must be built with GHC >= 8.8
+       ("ghc-bootstrap" ,ghc-8.10)
+       ("ghc-testsuite"
+        ,(origin
+           (method url-fetch)
+           (uri (string-append
+                  "https://www.haskell.org/ghc/dist/"
+                  version "/ghc-" version "-testsuite.tar.xz"))
+           (sha256
+            (base32
+             "1m5fzhr4gjn9ni8gxx7ag3fkbw1rspjzgv39mnfb0nkm5mw70v3s"))))
+       ,@(filter (match-lambda
+                   (("ghc-bootstrap" . _) #f)
+                   (("ghc-testsuite" . _) #f)
+                   (_ #t))
+                 (package-native-inputs ghc-8.10))))
+    (native-search-paths
+     (list (search-path-specification
+            (variable "GHC_PACKAGE_PATH")
+            (files (list (string-append "lib/ghc-" version)))
+            (file-pattern ".*\\.conf\\.d$")
+            (file-type 'directory))))))
+
 (define-public ghc ghc-8)
 
 ;;; haskell.scm ends here