Abandon flakes in favour of npins

Flakes copy the whole gigantic repo to store all the time, quickly eating all the drive capacity.

site/cabal.project

@@ -1,9 +0,0 @@
-packages: .
-
-source-repository-package
-  type: git
-  location: https://gitlab.com/tojnar.cz/hroch
-  tag: master
-
-package hakyll-contrib-tojnar
-  flags: -gd

site/mala-zahradka-pro-radost-cz.cabal

@@ -13,7 +13,7 @@ executable site
     hakyll >= 4.9 && < 4.16,
     hakyll-contrib-tojnar >= 0.2.1 && < 0.3.0,
     filepath >= 1.4 && < 1.5,
-    pandoc >= 2.0 && < 2.18,
+    pandoc >= 2.0 && < 2.20,
     process >= 1.6 && < 1.7,
     time >= 1.9 && < 1.12,
   ghc-options:

site/mala-zahradka-pro-radost-cz.nix

@@ -0,0 +1,43 @@
+{
+  mkDerivation,
+  base,
+  containers,
+  directory,
+  extra,
+  filepath,
+  hakyll,
+  hakyll-contrib-tojnar,
+  pandoc,
+  process,
+  time,
+  lib,
+}:
+
+mkDerivation {
+  pname = "mala-zahradka-pro-radost-cz";
+  version = "0.0.1";
+
+  # Keep the contents of the src/ directory and top-level .cabal file.
+  src = lib.sourceByRegex ./. [
+    "^src(/.+|$)"
+    "[^/]+\.cabal$"
+  ];
+
+  isLibrary = false;
+  isExecutable = true;
+
+  executableHaskellDepends = [
+    base
+    containers
+    directory
+    extra
+    filepath
+    hakyll
+    hakyll-contrib-tojnar
+    pandoc
+    process
+    time
+  ];
+
+  license = lib.licenses.mit;
+}