Merge pull request #69 from dschrempf/nix-flake

Nix flake

.gitignore

@@ -32,3 +32,5 @@ terraphast/
 test_scripts/
 vectorclass/
 zlib-1.2.7/
+/.direnv/
+/.envrc

flake.nix

@@ -0,0 +1,39 @@
+{
+  description = "IQ-TREE 2";
+
+  inputs.flake-utils.url = "github:numtide/flake-utils";
+
+  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable-small";
+
+  outputs =
+    { self
+    , flake-utils
+    , nixpkgs
+    }:
+    flake-utils.lib.eachDefaultSystem (
+      system:
+      let
+        # # For Nixpkgs and the NUR repository, the following two forms are
+        # # equivalent because the flake just imports the base directory.
+        pkgs = nixpkgs.legacyPackages.${system};
+        # pkgs = import nixpkgs {
+        #   inherit system;
+        #   config = { allowUnfree = true; };
+        # };
+      in
+      {
+        devShell = pkgs.mkShell {
+          packages = with pkgs; [
+            # See https://github.com/NixOS/nixpkgs/issues/59209.
+            bashInteractive
+          ];
+          nativeBuildInputs = with pkgs; [ cmake ];
+          buildInputs = with pkgs; [ boost eigen zlib ];
+
+          cmakeFlags = [
+            "-DIQTREE_FLAGS=omp"
+          ];
+        };
+      }
+    );
+}