osgXR: Update to 0.5.1

Update 3rdparty/osgXR to version 0.5.1, which fixes a windows build
error on Microsoft Visual Studio Community 2019 version 16.11.18.

3rdparty/osgXR/CHANGELOG.md

@@ -1,3 +1,12 @@
+Version 0.5.1
+-------------
+
+Highlights:
+ * Windows build fix: Fix missing IUnknown.
+
+Documentation:
+ * Settings: Fix typo in doxygen comment.
+
 Version 0.5.0
 -------------
 

3rdparty/osgXR/CMakeLists.txt

@@ -3,7 +3,7 @@ cmake_minimum_required(VERSION 3.11)
 
 set(osgXR_MAJOR_VERSION 0)
 set(osgXR_MINOR_VERSION 5)
-set(osgXR_PATCH_VERSION 0)
+set(osgXR_PATCH_VERSION 1)
 set(osgXR_SOVERSION 6)
 
 set(osgXR_VERSION "${osgXR_MAJOR_VERSION}.${osgXR_MINOR_VERSION}.${osgXR_PATCH_VERSION}")

3rdparty/osgXR/include/osgXR/Settings

@@ -186,7 +186,8 @@ class OSGXR_EXPORT Settings : public osg::Referenced
          * Specify an allowed environment blend mode.
          * The chosen environment blend mode is allowed for use, and may be
          * chosen if supported by OpenXR when none of the preferred environment
-         * blend modes specified by preferEnvBlenMode() are supported by OpenXR.
+         * blend modes specified by preferEnvBlendMode() are supported by
+         * OpenXR.
          * @param mode Environment blend mode to prefer.
          */
         void allowEnvBlendMode(BlendMode mode)

3rdparty/osgXR/src/OpenXR/GraphicsBindingWin32.h

@@ -9,6 +9,7 @@
 #include "GraphicsBinding.h"
 
 #include <osgViewer/api/Win32/GraphicsWindowWin32>
+#include <unknwn.h>
 
 #define XR_USE_GRAPHICS_API_OPENGL
 #define XR_USE_PLATFORM_WIN32