Do thread safe local static based initialization

apps/openmw/mwgui/mapwindow.cpp

@@ -774,12 +774,10 @@ namespace MWGui
         , mGlobalMapRender(std::make_unique<MWRender::GlobalMap>(localMapRender->getRoot(), workQueue))
         , mEditNoteDialog()
     {
-        static bool registered = false;
+        [[maybe_unused]] static const bool registered = [] {
-        if (!registered)
-        {
             MyGUI::FactoryManager::getInstance().registerFactory<MarkerWidget>("Widget");
-            registered = true;
+            return true;
-        }
+        }();
 
         mEditNoteDialog.setVisible(false);
         mEditNoteDialog.eventOkClicked += MyGUI::newDelegate(this, &MapWindow::onNoteEditOk);

apps/openmw/mwrender/npcanimation.cpp

@@ -401,14 +401,12 @@ namespace MWRender
     {
         if (mViewMode == VM_FirstPerson)
         {
-            static bool prototypeAdded = false;
+            [[maybe_unused]] static const bool prototypeAdded = [&] {
-            if (!prototypeAdded)
-            {
                 osg::ref_ptr<osgUtil::RenderBin> depthClearBin(new osgUtil::RenderBin);
                 depthClearBin->setDrawCallback(new DepthClearCallback());
                 osgUtil::RenderBin::addRenderBinPrototype("DepthClear", depthClearBin);
-                prototypeAdded = true;
+                return true;
-            }
+            }();
             mObjectRoot->getOrCreateStateSet()->setRenderBinDetails(
                 RenderBin_FirstPerson, "DepthClear", osg::StateSet::OVERRIDE_RENDERBIN_DETAILS);
         }

apps/openmw/mwrender/ripples.cpp

@@ -88,14 +88,13 @@ namespace MWRender
 
         if (mProgramBlobber != nullptr)
         {
-            static bool pipelineLogged = [&] {
+            [[maybe_unused]] static const bool pipelineLogged = [&] {
                 if (mUseCompute)
                     Log(Debug::Info) << "Initialized compute shader pipeline for water ripples";
                 else
                     Log(Debug::Info) << "Initialized fallback fragment shader pipeline for water ripples";
                 return true;
             }();
-            (void)pipelineLogged;
         }
 
         setCullCallback(new osg::NodeCallback);

apps/openmw/mwsound/ffmpegdecoder.cpp

@@ -522,16 +522,14 @@ namespace MWSound
 
         /* We need to make sure ffmpeg is initialized. Optionally silence warning
          * output from the lib */
-        static bool done_init = false;
+        [[maybe_unused]] static const bool doneInit = [] {
-        if (!done_init)
-        {
 // This is not needed anymore above FFMpeg version 4.0
 #if LIBAVCODEC_VERSION_INT < 3805796
             av_register_all();
 #endif
             av_log_set_level(AV_LOG_ERROR);
-            done_init = true;
+            return true;
-        }
+        }();
     }
 
     FFmpegDecoder::~FFmpegDecoder()

apps/openmw/mwworld/scene.cpp

@@ -1273,13 +1273,12 @@ namespace MWWorld
         const std::size_t leftCapacity = mPreloader->getMaxCacheSize() - mPreloader->getCacheSize();
         if (cells.size() > leftCapacity)
         {
-            static bool logged = [&] {
+            [[maybe_unused]] static const bool logged = [&] {
                 Log(Debug::Warning) << "Not enough cell preloader cache capacity to preload exterior cells, consider "
                                        "increasing \"preload cell cache max\" up to "
                                     << (mPreloader->getCacheSize() + cells.size());
                 return true;
             }();
-            (void)logged;
             cells.resize(leftCapacity);
         }
 

components/sceneutil/depth.hpp

@@ -95,13 +95,10 @@ namespace SceneUtil
 
         static void setReversed(bool reverseZ)
         {
-            static bool init = false;
+            [[maybe_unused]] static const bool init = [&] {
-
-            if (!init)
-            {
                 AutoDepth::sReversed = reverseZ;
-                init = true;
+                return true;
-            }
+            }();
         }
 
         static bool isReversed()