Improve Nix support (#5777)

* Fix FindOpusFile NixOS bug

* better documentation

CMake/FindOpusFile.cmake

@@ -6,9 +6,16 @@
 #   OPUSFILE_LIBRARY     - Path to the opusfile library
 #   OPUSFILE_LIBRARIES   - Full list of libraries to link (opusfile, opus, ogg)
 
+# Use pkg-config to find opusfile if available
+find_package(PkgConf)
+if(PKG_CONFIG_FOUND)
+    pkg_check_modules(PC_OPUSFILE QUIET opusfile)
+endif()
+
 # Search for the OpusFile header
 find_path(OPUSFILE_INCLUDE_DIR
     NAMES opusfile.h
+    HINTS ${PC_OPUSFILE_INCLUDE_DIRS}
     PATHS /usr/include/opus /usr/local/include/opus /opt/local/include/opus /opt/homebrew/include/opus
     DOC "Directory where opusfile.h is located"
 )
@@ -16,6 +23,7 @@ find_path(OPUSFILE_INCLUDE_DIR
 # Search for the OpusFile library
 find_library(OPUSFILE_LIBRARY
     NAMES opusfile
+    HINTS ${PC_OPUSFILE_LIBRARY_DIRS}
     DOC "Path to the libopusfile library"
 )
 

docs/BUILDING.md

@@ -119,6 +119,72 @@ zypper in gcc gcc-c++ git cmake ninja SDL2-devel libpng16-devel libzip-devel lib
 # or using clang
 zypper in clang libstdc++-devel git cmake ninja SDL2-devel libpng16-devel libzip-devel libzip-tools nlohmann_json-devel tinyxml2-devel spdlog-devel
 ```
+#### Nix
+You can use a `flake.nix` file to instantly setup a development environment using [Nix](https://nixos.org/). Write this `flake.nix` file in the root directory:
+
+```nix
+{
+  description = "Shipwright development environment";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = { self, nixpkgs, flake-utils }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = nixpkgs.legacyPackages.${system};
+      in
+      {
+        devShells.default = pkgs.mkShell {
+          buildInputs = with pkgs; [
+            # Build tools
+            clang
+            git
+            cmake
+            ninja
+            lsb-release
+            pkg-config
+
+            # SDL2 libraries
+            SDL2
+            SDL2.dev
+            SDL2_net
+
+            # Other libraries
+            libpng
+            libzip
+            nlohmann_json
+            tinyxml-2
+            spdlog
+            libGL
+            libGL.dev
+            bzip2
+
+            # X11 libraries
+            xorg.libX11
+
+            # Audio libraries
+            libogg
+            libogg.dev
+            libvorbis
+            libvorbis.dev
+            libopus
+            libopus.dev
+            opusfile
+            opusfile.dev
+          ];
+          shellHook = ''
+            echo "Shipwright development environment loaded"
+            echo "Available tools: clang, git, cmake, ninja"
+          '';
+        };
+      });
+}
+```
+
+Now type `nix develop` and you will be dropped into a shell with all dependencies, ensuring that all build commands work.
 
 ### Build