[General] Fix standalone server build

CMakeLists.txt

@@ -736,7 +736,10 @@ if (WIN32)
     endforeach(d)
 
     set_target_properties(components PROPERTIES COMPILE_FLAGS "${WARNINGS} ${MT_BUILD}")
-    set_target_properties(osg-ffmpeg-videoplayer PROPERTIES COMPILE_FLAGS "${WARNINGS} ${MT_BUILD}")
+
+    if (BUILD_OPENMW)
+        set_target_properties(osg-ffmpeg-videoplayer PROPERTIES COMPILE_FLAGS "${WARNINGS} ${MT_BUILD}")
+    endif()
 
     if (BUILD_BSATOOL)
         set_target_properties(bsatool PROPERTIES COMPILE_FLAGS "${WARNINGS} ${MT_BUILD}")