3 files changed, 41 insertions, 13 deletions
diff --git a/krebs/5pkgs/haskell/blessings.nix b/krebs/5pkgs/haskell/blessings.nix
index 55f2d17d0..b0e81fdc1 100644
--- a/krebs/5pkgs/haskell/blessings.nix
+++ b/krebs/5pkgs/haskell/blessings.nix
@@ -6,19 +6,10 @@ with import <stockholm/lib>;
       version = "1.1.0";
       sha256 = "1k908zap3694fcxdk4bb29s54b0lhdh557y10ybjskfwnym7szn1";
     };
-    "18.09" = {
-      version = "2.2.0";
-      sha256 = "1pb56dgf3jj2kq3cbbppwzyg3ccgqy9xara62hkjwyxzdx20clk1";
-    };
-    "19.03" = {
-      version = "2.2.0";
-      sha256 = "1pb56dgf3jj2kq3cbbppwzyg3ccgqy9xara62hkjwyxzdx20clk1";
-    };
-    "19.09" = {
-      version = "2.2.0";
-      sha256 = "1pb56dgf3jj2kq3cbbppwzyg3ccgqy9xara62hkjwyxzdx20clk1";
-    };
-  }.${versions.majorMinor version};
+  }.${versions.majorMinor version} or {
+    version = "2.2.0";
+    sha256 = "1pb56dgf3jj2kq3cbbppwzyg3ccgqy9xara62hkjwyxzdx20clk1";
+  };
 
 in mkDerivation {
   pname = "blessings";
diff --git a/krebs/5pkgs/override/default.nix b/krebs/5pkgs/override/default.nix
new file mode 100644
index 000000000..704831823
--- /dev/null
+++ b/krebs/5pkgs/override/default.nix
@@ -0,0 +1,12 @@
+with import <stockholm/lib>;
+self: super: {
+
+  exim = super.exim.overrideAttrs (old: rec {
+    name = warnOldVersion old.name "exim-4.92.2";
+    src = self.fetchurl {
+      url = "https://ftp.exim.org/pub/exim/exim4/${name}.tar.xz";
+      sha256 = "0m56jsh2fzvwj4rdpcc3pkd5vsi40cjrpzalis7l1zq33m4axmq1";
+    };
+  });
+
+}
diff --git a/krebs/5pkgs/simple/nix-prefetch-github.nix b/krebs/5pkgs/simple/nix-prefetch-github.nix
new file mode 100644
index 000000000..14096c33f
--- /dev/null
+++ b/krebs/5pkgs/simple/nix-prefetch-github.nix
@@ -0,0 +1,25 @@
+{ curl, jq, nix, writeDashBin }:
+
+writeDashBin "nix-prefetch-github" ''
+  # usage: nix-prefetch-github OWNER REPO [REF]
+  set -efu
+
+  owner=$1
+  repo=$2
+  ref=''${3-master}
+
+  info_url=https://api.github.com/repos/$owner/$repo/commits/$ref
+  info=$(${curl}/bin/curl -fsS "$info_url")
+  rev=$(printf %s "$info" | ${jq}/bin/jq -r .sha)
+
+  name=$owner-$repo-$ref
+  url=https://github.com/$owner/$repo/tarball/$rev
+  sha256=$(${nix}/bin/nix-prefetch-url --name "$name" --unpack "$url")
+
+  export owner repo rev sha256
+  ${jq}/bin/jq -n '
+    env | {
+      owner, repo, rev, sha256
+    }
+  '
+''