home/packages: add forester

this was much too much work. to summarise:
- ocamlc is weird and does not at all play nice with nix
- nixpkgs.ocamlPackages seems to not have any good way to deal with
  multiple package versions, and forester needs several different
  versions than are in nixpkgs
- forester itself has a flake which one is supposed to use with Nix; it
  uses tweag's opam-nix construct
- which for some bizarre reason cannot be imported the way I import all
  my other flakes, and I do not understand why
- so I gave up for now and import it via flake-compat, unfortunately
  tying me to an old nixpkgs pin (~June), which hopefully does not
  influence too much of the output
- forester's flake's default output is a cross-compiled musl version (???)
- so use the one in legacyPackages instead

1 files changed, 25 insertions, 0 deletions

diff --git a/inputs.nix b/inputs.nix
index b31981b..9cb3bf3 100644
--- a/inputs.nix
+++ b/inputs.nix
@@ -65,5 +65,30 @@ let
     lix-overlay = import "${sources.lix-nixos-module}/overlay.nix" {
       lix = sources.lix // { rev = sources.lix.revision; };
     };
+
+
+    ###### Forester stuff
+
+    flake-compat = import sources.flake-compat;
+
+    # currently unused
+    opam2json = callFlake "opam2json" {
+      nixpkgs = nixpkgs-flake;
+    };
+    # opam-nix does not want to be called like this; i do not know why
+    # opam-nix = callFlake "opam-nix"{
+    #   inherit (sources) opam-repository opam-overlays mirage-opam-overlays;
+    #   inherit (inputs) flake-utils opam2json flake-compat;
+    #   nixpkgs = nixpkgs-unstable-flake;
+    # };
+    # so i gave up an use the flake-compat'd version instead, which uses an
+    # old nixpkgs pin i cannot easily change ...
+    opam-nix = (flake-compat { src = sources.opam-nix.outPath; }).defaultNix;
+
+    ocaml-forester = callFlake "ocaml-forester" {
+      nixpkgs = nixpkgs-flake;
+      inherit (inputs) opam-nix flake-utils;
+      inherit (sources) opam-repository;
+    };
   };
 in inputs