Fix compilation with -std=23

/usr/include/c++/15.2.1/bits/unique_ptr.h: In instantiation of ‘constexpr std::__detail::__unique_ptr_t<_Tp> std::make_unique(_Args&& ...) [with _Tp = Shader::HotReloadManager; _Args = {}; __detail::__unique_ptr_t<_Tp> = __detail::__unique_ptr_t<Shader::HotReloadManager>]’:
/home/elsid/dev/openmw/components/shader/shadermanager.cpp:83:63:   required from here
   83 |         mHotReloadManager = std::make_unique<HotReloadManager>();
      |                             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~
/usr/include/c++/15.2.1/bits/unique_ptr.h:1085:30: error: invalid use of incomplete type ‘struct Shader::HotReloadManager’
 1085 |     { return unique_ptr<_Tp>(new _Tp(std::forward<_Args>(__args)...)); }
      |                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
components/shader/shadermanager.hpp:24:12: note: forward declaration of ‘struct Shader::HotReloadManager’
   24 |     struct HotReloadManager;
      |            ^~~~~~~~~~~~~~~~

components/shader/shadermanager.cpp

@@ -74,22 +74,6 @@ namespace
             += static_cast<int>(std::count(source.begin() + lineDirectivePosition, source.begin() + foundPos, '\n'));
         return lineNumber;
     }
-}
-
-namespace Shader
-{
-
-    ShaderManager::ShaderManager()
-    {
-        mHotReloadManager = std::make_unique<HotReloadManager>();
-    }
-
-    ShaderManager::~ShaderManager() = default;
-
-    void ShaderManager::setShaderPath(const std::filesystem::path& path)
-    {
-        mPath = path;
-    }
 
     bool addLineDirectivesAfterConditionalBlocks(std::string& source)
     {
@@ -122,7 +106,7 @@ namespace Shader
     // Adjusts #line statements accordingly and detects cyclic includes.
     // cycleIncludeChecker is the set of files that include this file directly or indirectly, and is intentionally not a
     // reference to allow automatic cleanup.
-    static bool parseIncludes(const std::filesystem::path& shaderPath, std::string& source, const std::string& fileName,
+    bool parseIncludes(const std::filesystem::path& shaderPath, std::string& source, const std::string& fileName,
         int& fileNumber, std::set<std::filesystem::path> cycleIncludeChecker,
         std::set<std::filesystem::path>& includedFiles)
     {
@@ -195,6 +179,127 @@ namespace Shader
         }
         return true;
     }
+}
+
+namespace Shader
+{
+    struct HotReloadManager
+    {
+        using KeysHolder = std::set<ShaderManager::MapKey>;
+
+        std::unordered_map<std::string, KeysHolder> mShaderFiles;
+        std::unordered_map<std::string, std::set<std::filesystem::path>> templateIncludedFiles;
+        std::filesystem::file_time_type mLastAutoRecompileTime;
+        bool mHotReloadEnabled;
+        bool mTriggerReload;
+
+        HotReloadManager()
+        {
+            mTriggerReload = false;
+            mHotReloadEnabled = false;
+            mLastAutoRecompileTime = std::filesystem::file_time_type::clock::now();
+        }
+
+        void addShaderFiles(const std::string& templateName, const ShaderManager::DefineMap& defines)
+        {
+            const std::set<std::filesystem::path>& shaderFiles = templateIncludedFiles[templateName];
+            for (const std::filesystem::path& file : shaderFiles)
+            {
+                mShaderFiles[Files::pathToUnicodeString(file)].insert(std::make_pair(templateName, defines));
+            }
+        }
+
+        void update(ShaderManager& manager, osgViewer::Viewer& viewer)
+        {
+            auto timeSinceLastCheckMillis = std::chrono::duration_cast<std::chrono::milliseconds>(
+                std::filesystem::file_time_type::clock::now() - mLastAutoRecompileTime);
+            if ((mHotReloadEnabled && timeSinceLastCheckMillis.count() > 200) || mTriggerReload == true)
+            {
+                reloadTouchedShaders(manager, viewer);
+            }
+            mTriggerReload = false;
+        }
+
+        void reloadTouchedShaders(ShaderManager& manager, osgViewer::Viewer& viewer)
+        {
+            bool threadsRunningToStop = false;
+            for (auto& [pathShaderToTest, shaderKeys] : mShaderFiles)
+            {
+                const std::filesystem::file_time_type writeTime = std::filesystem::last_write_time(pathShaderToTest);
+                if (writeTime.time_since_epoch() > mLastAutoRecompileTime.time_since_epoch())
+                {
+                    if (!threadsRunningToStop)
+                    {
+                        threadsRunningToStop = viewer.areThreadsRunning();
+                        if (threadsRunningToStop)
+                            viewer.stopThreading();
+                    }
+
+                    for (const auto& [templateName, shaderDefines] : shaderKeys)
+                    {
+                        ShaderManager::ShaderMap::iterator shaderIt
+                            = manager.mShaders.find(std::make_pair(templateName, shaderDefines));
+                        if (shaderIt == manager.mShaders.end())
+                        {
+                            Log(Debug::Error) << "Failed to find shader " << templateName;
+                            continue;
+                        }
+
+                        ShaderManager::TemplateMap::iterator templateIt = manager.mShaderTemplates.find(
+                            templateName); // Can't be Null, if we're here it means the template was added
+                        assert(templateIt != manager.mShaderTemplates.end());
+                        std::string& shaderSource = templateIt->second;
+                        std::set<std::filesystem::path> insertedPaths;
+                        std::filesystem::path path = (std::filesystem::path(manager.mPath) / templateName);
+                        std::ifstream stream;
+                        stream.open(path);
+                        if (stream.fail())
+                        {
+                            Log(Debug::Error)
+                                << "Failed to open " << path << ": " << std::generic_category().message(errno);
+                            continue;
+                        }
+                        std::stringstream buffer;
+                        buffer << stream.rdbuf();
+
+                        // parse includes
+                        int fileNumber = 1;
+                        std::string source = buffer.str();
+                        if (!addLineDirectivesAfterConditionalBlocks(source)
+                            || !parseIncludes(std::filesystem::path(manager.mPath), source, templateName, fileNumber,
+                                {}, insertedPaths))
+                        {
+                            break;
+                        }
+                        shaderSource = std::move(source);
+
+                        std::vector<std::string> linkedShaderNames;
+                        if (!manager.createSourceFromTemplate(
+                                shaderSource, linkedShaderNames, templateName, shaderDefines))
+                        {
+                            break;
+                        }
+                        shaderIt->second->setShaderSource(shaderSource);
+                    }
+                }
+            }
+            if (threadsRunningToStop)
+                viewer.startThreading();
+            mLastAutoRecompileTime = std::filesystem::file_time_type::clock::now();
+        }
+    };
+
+    ShaderManager::ShaderManager()
+    {
+        mHotReloadManager = std::make_unique<HotReloadManager>();
+    }
+
+    ShaderManager::~ShaderManager() = default;
+
+    void ShaderManager::setShaderPath(const std::filesystem::path& path)
+    {
+        mPath = path;
+    }
 
     bool parseForeachDirective(std::string& source, const std::string& templateName, size_t foundPos)
     {
@@ -399,112 +504,6 @@ namespace Shader
         return true;
     }
 
-    struct HotReloadManager
-    {
-        using KeysHolder = std::set<ShaderManager::MapKey>;
-
-        std::unordered_map<std::string, KeysHolder> mShaderFiles;
-        std::unordered_map<std::string, std::set<std::filesystem::path>> templateIncludedFiles;
-        std::filesystem::file_time_type mLastAutoRecompileTime;
-        bool mHotReloadEnabled;
-        bool mTriggerReload;
-
-        HotReloadManager()
-        {
-            mTriggerReload = false;
-            mHotReloadEnabled = false;
-            mLastAutoRecompileTime = std::filesystem::file_time_type::clock::now();
-        }
-
-        void addShaderFiles(const std::string& templateName, const ShaderManager::DefineMap& defines)
-        {
-            const std::set<std::filesystem::path>& shaderFiles = templateIncludedFiles[templateName];
-            for (const std::filesystem::path& file : shaderFiles)
-            {
-                mShaderFiles[Files::pathToUnicodeString(file)].insert(std::make_pair(templateName, defines));
-            }
-        }
-
-        void update(ShaderManager& manager, osgViewer::Viewer& viewer)
-        {
-            auto timeSinceLastCheckMillis = std::chrono::duration_cast<std::chrono::milliseconds>(
-                std::filesystem::file_time_type::clock::now() - mLastAutoRecompileTime);
-            if ((mHotReloadEnabled && timeSinceLastCheckMillis.count() > 200) || mTriggerReload == true)
-            {
-                reloadTouchedShaders(manager, viewer);
-            }
-            mTriggerReload = false;
-        }
-
-        void reloadTouchedShaders(ShaderManager& manager, osgViewer::Viewer& viewer)
-        {
-            bool threadsRunningToStop = false;
-            for (auto& [pathShaderToTest, shaderKeys] : mShaderFiles)
-            {
-                const std::filesystem::file_time_type writeTime = std::filesystem::last_write_time(pathShaderToTest);
-                if (writeTime.time_since_epoch() > mLastAutoRecompileTime.time_since_epoch())
-                {
-                    if (!threadsRunningToStop)
-                    {
-                        threadsRunningToStop = viewer.areThreadsRunning();
-                        if (threadsRunningToStop)
-                            viewer.stopThreading();
-                    }
-
-                    for (const auto& [templateName, shaderDefines] : shaderKeys)
-                    {
-                        ShaderManager::ShaderMap::iterator shaderIt
-                            = manager.mShaders.find(std::make_pair(templateName, shaderDefines));
-                        if (shaderIt == manager.mShaders.end())
-                        {
-                            Log(Debug::Error) << "Failed to find shader " << templateName;
-                            continue;
-                        }
-
-                        ShaderManager::TemplateMap::iterator templateIt = manager.mShaderTemplates.find(
-                            templateName); // Can't be Null, if we're here it means the template was added
-                        assert(templateIt != manager.mShaderTemplates.end());
-                        std::string& shaderSource = templateIt->second;
-                        std::set<std::filesystem::path> insertedPaths;
-                        std::filesystem::path path = (std::filesystem::path(manager.mPath) / templateName);
-                        std::ifstream stream;
-                        stream.open(path);
-                        if (stream.fail())
-                        {
-                            Log(Debug::Error)
-                                << "Failed to open " << path << ": " << std::generic_category().message(errno);
-                            continue;
-                        }
-                        std::stringstream buffer;
-                        buffer << stream.rdbuf();
-
-                        // parse includes
-                        int fileNumber = 1;
-                        std::string source = buffer.str();
-                        if (!addLineDirectivesAfterConditionalBlocks(source)
-                            || !parseIncludes(std::filesystem::path(manager.mPath), source, templateName, fileNumber,
-                                {}, insertedPaths))
-                        {
-                            break;
-                        }
-                        shaderSource = std::move(source);
-
-                        std::vector<std::string> linkedShaderNames;
-                        if (!manager.createSourceFromTemplate(
-                                shaderSource, linkedShaderNames, templateName, shaderDefines))
-                        {
-                            break;
-                        }
-                        shaderIt->second->setShaderSource(shaderSource);
-                    }
-                }
-            }
-            if (threadsRunningToStop)
-                viewer.startThreading();
-            mLastAutoRecompileTime = std::filesystem::file_time_type::clock::now();
-        }
-    };
-
     osg::ref_ptr<osg::Shader> ShaderManager::getShader(
         std::string templateName, const ShaderManager::DefineMap& defines, std::optional<osg::Shader::Type> type)
     {