hakyll: updated to v4.15

jfdic-web.cabal

@@ -6,7 +6,7 @@ cabal-version:      >= 1.10
 executable site
   main-is:          site.hs
   build-depends:    base == 4.*
-                  , hakyll == 4.14.*
+                  , hakyll == 4.15.*
                   , containers == 0.6.*
                   , filepath == 1.4.*
                   , pandoc

release.nix

@@ -1,9 +1,5 @@
-let
-  sources = import ./nix/sources.nix;
-in
-{ compiler ? "ghc8104"
-, pkgs ? import sources.nixpkgs { }
-}:
+let sources = import ./nix/sources.nix;
+in { compiler ? "ghc8107", pkgs ? import sources.nixpkgs { } }:
 
 let
   inherit (pkgs.lib.trivial) flip pipe;
@@ -11,12 +7,10 @@ let
 
   haskellPackages = pkgs.haskell.packages.${compiler}.override {
     overrides = hpNew: hpOld: {
-      hakyll =
-        pipe
-           hpOld.hakyll
-           [ (flip appendPatch ./hakyll.patch)
-             (flip appendConfigureFlags [ "-f" "watchServer" "-f" "previewServer" ])
-           ];
+      hakyll = pipe hpOld.hakyll [
+        (flip appendPatch ./hakyll.patch)
+        (flip appendConfigureFlags [ "-f" "watchServer" "-f" "previewServer" ])
+      ];
 
       jfdic-web = hpNew.callCabal2nix "jfdic-web" ./. { };
 
@@ -25,18 +19,16 @@ let
   };
 
   project = haskellPackages.jfdic-web;
-in
-{
+in {
   project = project;
 
   shell = haskellPackages.shellFor {
-    packages = p: with p; [
-      project
-    ];
+    packages = p: with p; [ project ];
     buildInputs = with haskellPackages; [
-      ghcid       # GHCi based IDE
-      hlint       # or ormolu
-      pkgs.niv    # Nix dependency management
+      ghcid # GHCi based IDE
+      hlint # or ormolu
+      pkgs.niv
+      zlib
     ];
     withHoogle = true;
   };