Fix Nix Package by adding shiggy as an Input.

flake.nix

@@ -3,9 +3,13 @@
 
   inputs = {
     nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
+    shiggy = {
+      url   = "github:4jcraft/shiggy/main";
+      flake = false;
+    };
   };
 
-  outputs = { self, nixpkgs, ... }:
+  outputs = { self, nixpkgs, shiggy, ... }:
   let
     allSystems = [
       "x86_64-linux"
@@ -13,7 +17,6 @@
       "x86_64-darwin"
       "aarch64-darwin"
     ];
-
     forAllSystems = f: nixpkgs.lib.genAttrs allSystems (system: f {
       pkgs = import nixpkgs { inherit system; };
     });
@@ -24,9 +27,13 @@
         default = pkgs.clangStdenv.mkDerivation {
           pname   = "4jcraft";
           version = "0.1.0";
-
           src = ./.;
 
+          preConfigure = ''
+            mkdir -p subprojects/shiggy
+            cp -r ${shiggy}/. subprojects/shiggy/
+          '';
+
           buildInputs = with pkgs; [
             openssl.dev
             libGL
@@ -47,7 +54,6 @@
           installPhase = ''
             mkdir -p $out/share/4jcraft
             cp -r Minecraft.Client/. $out/share/4jcraft/
-
             mkdir -p $out/bin
             makeWrapper $out/share/4jcraft/Minecraft.Client \
               $out/bin/4jcraft \