Restore false-positive unused includes

They're needed on MacOS as SDL_opengl_gletx.h doesn't define them there.

They don't actually work on MacOS, so long-term, the code that uses
these defines should be changed to use #ifdef to check they're available
before using them.

apps/openmw/mwrender/postprocessor.cpp

@@ -15,6 +15,7 @@
 #include <components/misc/strings/algorithm.hpp>
 #include <components/misc/strings/lower.hpp>
 #include <components/resource/scenemanager.hpp>
+#include <components/sceneutil/color.hpp>
 #include <components/sceneutil/depth.hpp>
 #include <components/sceneutil/nodecallback.hpp>
 #include <components/settings/settings.hpp>

components/fx/parse_constants.hpp

@@ -9,6 +9,8 @@
 #include <osg/Image>
 #include <osg/Texture>
 
+#include <components/sceneutil/color.hpp>
+
 #include "technique.hpp"
 
 namespace fx

components/stereo/frustum.cpp

@@ -15,6 +15,7 @@
 #include <map>
 #include <string>
 
+#include <components/sceneutil/color.hpp>
 #include <components/sceneutil/mwshadowtechnique.hpp>
 
 #include <components/settings/settings.hpp>

components/stereo/stereomanager.cpp

@@ -19,6 +19,7 @@
 
 #include <components/misc/constants.hpp>
 
+#include <components/sceneutil/color.hpp>
 #include <components/sceneutil/depth.hpp>
 #include <components/sceneutil/statesetupdater.hpp>