haskellPackages.spacecookie: enable extra tests, install man pages

Add an override to configuration-common.nix adding the following
features to the derivation:

* Let test suite discover the built spacecookie binary, so it doesn't
  skip integration tests (which are very cheap and take just over 1s).
* Install man pages shipped in the sdist. (If someone is eager to get
  rid of this override feel free to explain to me how to achieve this
  without a Custom build-type which pulls in thousands of modules from
  Cabal. :p)

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

@@ -1664,4 +1664,16 @@ self: super: {
   # Test suite does not compile.
   feed = dontCheck super.feed;
 
+  spacecookie = overrideCabal super.spacecookie (old: {
+    buildTools = (old.buildTools or []) ++ [ pkgs.installShellFiles ];
+    # let testsuite discover the resulting binary
+    preCheck = ''
+      export SPACECOOKIE_TEST_BIN=./dist/build/spacecookie/spacecookie
+    '' + (old.preCheck or "");
+    # install man pages shipped in the sdist
+    postInstall = ''
+      installManPage docs/man/*
+    '' + (old.postInstall or "");
+  });
+
 } // import ./configuration-tensorflow.nix {inherit pkgs haskellLib;} self super