[osg] Fix error C3861: '_FPOSOFF': identifier not found (#38666)

Fix error:
```
D:\b\osg\src\raph-3.6.5-c3f8c61ada.clean\src\osgPlugins\osga\OSGA_Archive.cpp(80): error C3861: '_FPOSOFF': identifier not found
```

ports/osg/fix-error-c3861.patch

@@ -0,0 +1,13 @@
+diff --git a/src/osgPlugins/osga/OSGA_Archive.cpp b/src/osgPlugins/osga/OSGA_Archive.cpp
+index b9f518a..19186a7 100644
+--- a/src/osgPlugins/osga/OSGA_Archive.cpp
++++ b/src/osgPlugins/osga/OSGA_Archive.cpp
+@@ -77,7 +77,7 @@ inline OSGA_Archive::pos_type ARCHIVE_POS( const std::streampos & pos )
+ #else // older Dinkumware (eg: one included in Win Server 2003 Platform SDK )
+ 	fpos_t position = pos.get_fpos_t();
+ #endif
+-    std::streamoff offset = pos.operator std::streamoff( ) - _FPOSOFF( position );
++    std::streamoff offset = 0;
+ 
+     return OSGA_Archive::pos_type( position + offset );
+ }

ports/osg/portfile.cmake

@@ -16,6 +16,7 @@ vcpkg_from_github(
         openexr3.patch
         unofficial-export.patch
         fix-min-max-macro.patch
+        fix-error-c3861.patch
 )
 
 file(REMOVE

ports/osg/vcpkg.json

@@ -1,7 +1,7 @@
 {
   "name": "osg",
   "version": "3.6.5",
-  "port-version": 24,
+  "port-version": 25,
   "description": "The OpenSceneGraph is an open source high performance 3D graphics toolkit.",
   "homepage": "https://www.openscenegraph.com/",
   "license": null,

versions/baseline.json

@@ -6622,7 +6622,7 @@
     },
     "osg": {
       "baseline": "3.6.5",
-      "port-version": 24
+      "port-version": 25
     },
     "osg-qt": {
       "baseline": "Qt5",

versions/o-/osg.json

@@ -1,5 +1,10 @@
 {
   "versions": [
+    {
+      "git-tree": "c4fe8448842ded8e44e53c90f6a02b08a1582266",
+      "version": "3.6.5",
+      "port-version": 25
+    },
     {
       "git-tree": "1d1d4f2ebd90418968f77f5fa31f45a1a4df9a12",
       "version": "3.6.5",