Add flake.nix

flake.nix

@@ -0,0 +1,48 @@
+{
+  description = "EmuHawk is a multi-system emulator written in C#. As well as quality-of-life features for casual players, it also has recording/playback and debugging tools, making it the first choice for TASers (Tool-Assisted Speedrunners).";
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/release-24.05";
+  };
+  outputs =
+    inputs@{ self, nixpkgs, ... }:
+    with builtins;
+    let
+      std = nixpkgs.lib;
+      systems = [
+        # this is currently the only supported system, according to https://github.com/TASEmulators/BizHawk/issues/1430#issue-396452488
+        "x86_64-linux"
+      ];
+      nixpkgsFor = std.genAttrs systems (
+        system:
+        import nixpkgs {
+          localSystem = builtins.currentSystem or system;
+          crossSystem = system;
+          overlays = [ ];
+        }
+      );
+      # import the derivations from default.nix for the given system & package set
+      importDefaultDerivationsWith =
+        system: pkgs:
+        # ./default.nix outputs some non-derivation attributes, so we have to filter those out
+        (std.filterAttrs (name: val: std.isDerivation val) (import ./default.nix { inherit system pkgs; }));
+    in
+    {
+      packages = mapAttrs (
+        system: pkgs:
+        (importDefaultDerivationsWith system pkgs)
+        // {
+          default = self.packages.${system}.emuhawk-latest-bin;
+        }
+      ) nixpkgsFor;
+      devShells = mapAttrs (
+        system: pkgs:
+        # ./shell.nix outputs some non-derivation attributes and some extraneous derivations, so we have to filter those out
+        (std.filterAttrs (
+          name: val: std.isDerivation val && name != "stdenv" && name != "out" && name != "inputDerivation"
+        ) (import ./shell.nix { inherit system pkgs; }))
+        // {
+          default = self.devShells.${system}.emuhawk-latest;
+        }
+      ) nixpkgsFor;
+    };
+}