haskellPackages.hashable: make test suite work with random 1.2.0

hashable's test suite pins random to < 1.2 even in the latest release on
hackage, but lifting the bound fixes the build without any issues. Using
a patch so we are reminded to remove it when it's unnecessary.

pkgs/development/haskell-modules/configuration-common.nix

@@ -1937,4 +1937,19 @@ EOT
   # https://github.com/kcsongor/generic-lens/issues/133
   generic-optics = dontCheck super.generic-optics;
 
+  # 2021-05-19: Allow random 1.2.0
+  # Remove at (presumably next release) which is > 1.3.1.0
+  hashable = overrideCabal super.hashable (drv: {
+    patches = [
+      (pkgs.fetchpatch {
+        url = "https://github.com/haskell-unordered-containers/hashable/commit/78fa8fdb4f8bec5d221f34110d6afa0d0a00b5f9.patch";
+        sha256 = "0bzgp9qf53zk4rzk73x5cf2kfqncvlmihcallpplaibpslzalyi4";
+      })
+    ] ++ (drv.patches or []);
+    # fix line endings preventing patch from applying
+    prePatch = ''
+      ${pkgs.dos2unix}/bin/dos2unix hashable.cabal
+    '' + (drv.prePatch or "");
+  });
+
 } // import ./configuration-tensorflow.nix {inherit pkgs haskellLib;} self super