nix: add support for non-flake builds

default.nix

@@ -0,0 +1 @@
+(import packages/nix/flake-compat.nix).defaultNix

flake.lock

@@ -1,5 +1,21 @@
 {
   "nodes": {
+    "flake-compat": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1641205782,
+        "narHash": "sha256-4jY7RCWUoZ9cKD8co0/4tFARpWB+57+r1bLLvXNJliY=",
+        "owner": "edolstra",
+        "repo": "flake-compat",
+        "rev": "b7547d3eed6f32d06102ead8991ec52ab0a4f1a7",
+        "type": "github"
+      },
+      "original": {
+        "owner": "edolstra",
+        "repo": "flake-compat",
+        "type": "github"
+      }
+    },
     "flake-utils": {
       "locked": {
         "lastModified": 1638122382,
@@ -65,6 +81,7 @@
     },
     "root": {
       "inputs": {
+        "flake-compat": "flake-compat",
         "flake-utils": "flake-utils",
         "libnbtplusplus": "libnbtplusplus",
         "nixpkgs": "nixpkgs",

flake.nix

@@ -2,6 +2,10 @@
   description = "PolyMC flake";
   inputs.nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
   inputs.flake-utils.url = "github:numtide/flake-utils";
+  inputs.flake-compat = { 
+    url = "github:edolstra/flake-compat";
+    flake = false;
+  };
   inputs.libnbtplusplus = {
     url = "github:multimc/libnbtplusplus";
     flake = false;
@@ -26,6 +30,7 @@
           };
         };
         
+        # 'nix flake check' fails
         overlay = (final: prev: rec { 
           polymc = prev.libsForQt5.callPackage ./packages/nix/polymc {
             inherit self;

packages/nix/flake-compat.nix

@@ -0,0 +1,9 @@
+let
+  lock = builtins.fromJSON (builtins.readFile ../../flake.lock);
+  inherit (lock.nodes.flake-compat.locked) rev narHash;
+  flake-compat = fetchTarball {
+    url = "https://github.com/edolstra/flake-compat/archive/${rev}.tar.gz";
+    sha256 = narHash;
+  };
+in
+import flake-compat { src = ../..; }

packages/nix/polymc/default.nix

@@ -2,8 +2,6 @@
 , mkDerivation
 , fetchFromGitHub
 , makeDesktopItem
-, substituteAll
-, fetchpatch
 , cmake
 , ninja
 , jdk8
@@ -15,14 +13,16 @@
 , libpulseaudio
 , qtbase
 , libGL
-# submodules
+
+# flake
 , self
 , submoduleNbt
 , submoduleQuazip
 }:
 
 let
-  gameLibraryPath = with xorg; lib.makeLibraryPath [
+  # Libraries required to run Minecraft
+  libpath = with xorg; lib.makeLibraryPath [
     libX11
     libXext
     libXcursor
@@ -31,6 +31,9 @@ let
     libpulseaudio
     libGL
   ]; 
+
+  # This variable will be passed to Minecraft by PolyMC
+  gameLibraryPath = libpath + ":/run/opengl-driver/lib";
 in
 
 mkDerivation rec {
@@ -42,7 +45,10 @@ mkDerivation rec {
   nativeBuildInputs = [ cmake ninja file makeWrapper ];
   buildInputs = [ qtbase jdk8 zlib ];
 
+  dontWrapQtApps = true;
+
   postUnpack = ''
+    # Copy submodules inputs
     rm -rf source/libraries/{libnbtplusplus,quazip}
     mkdir source/libraries/{libnbtplusplus,quazip}
     cp -a ${submoduleNbt}/* source/libraries/libnbtplusplus
@@ -69,11 +75,13 @@ mkDerivation rec {
   };
 
   postInstall = ''
-    install -Dm644 ../launcher/resources/multimc/scalable/launcher.svg $out/share/pixmaps/multimc.svg
-    install -Dm755 ${desktopItem}/share/applications/polymc.desktop -t $out/share/applications
+    install -Dm644 ../launcher/resources/multimc/scalable/launcher.svg $out/share/pixmaps/polymc.svg
+    install -Dm644 ${desktopItem}/share/applications/polymc.desktop $out/share/applications/org.polymc.PolyMC.desktop
+
     # xorg.xrandr needed for LWJGL [2.9.2, 3) https://github.com/LWJGL/lwjgl/issues/128
     wrapProgram $out/bin/polymc \
-      --set GAME_LIBRARY_PATH /run/opengl-driver/lib:${gameLibraryPath} \
+      "''${qtWrapperArgs[@]}" \
+      --set GAME_LIBRARY_PATH ${gameLibraryPath} \
       --prefix PATH : ${lib.makeBinPath [ xorg.xrandr jdk ]}
   '';
 }