add flake.nix

flake.nix

@@ -0,0 +1,59 @@
+{
+  description = "Nim-SDS build flake";
+
+  nixConfig = {
+    extra-substituters = [ "https://nix-cache.status.im/" ];
+    extra-trusted-public-keys = [ "nix-cache.status.im-1:x/93lOfLU+duPplwMSBR+OlY4+mo+dCN7n0mr4oPwgY=" ];
+  };
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs?rev=f44bd8ca21e026135061a0a57dcf3d0775b67a49";
+  };
+
+  outputs = { self, nixpkgs }:
+    let
+      stableSystems = [
+        "x86_64-linux" "aarch64-linux"
+        "x86_64-darwin" "aarch64-darwin"
+        "x86_64-windows" "i686-linux"
+        "i686-windows"
+      ];
+
+      forAllSystems = f: nixpkgs.lib.genAttrs stableSystems (system: f system);
+
+      pkgsFor = forAllSystems (
+        system: import nixpkgs {
+          inherit system;
+          config = {
+            android_sdk.accept_license = true;
+            allowUnfree = true;
+          };
+          overlays =  [
+            (final: prev: {
+              androidEnvCustom = prev.callPackage ./nix/pkgs/android-sdk { };
+              androidPkgs = final.androidEnvCustom.pkgs;
+              androidShell = final.androidEnvCustom.shell;
+            })
+          ];
+        }
+      );
+
+    in rec {
+      packages = forAllSystems (system: let
+        pkgs = pkgsFor.${system};
+      in rec {
+        libsds-android-arm64 = pkgs.callPackage ./nix/default.nix {
+          inherit stableSystems;
+          src = self;
+          targets = ["libsds-android-arm64"]; 
+          androidArch = "aarch64-linux-android";
+          abidir = "arm64-v8a";
+        };
+        default = libsds-android-arm64;
+      });
+
+      devShells = forAllSystems (system: {
+        default = pkgsFor.${system}.callPackage ./nix/shell.nix {};
+      });
+    };
+}