Error in dyn.load(sprintf("testRemoveFinalizers%s", .Platform$dynlib.ext)) : 
  unable to load shared object '/Users/duncan/GitWorkingArea/XML/testRemoveFinalizers.so':
  dlopen(/Users/duncan/GitWorkingArea/XML/testRemoveFinalizers.so, 6): Symbol not found: _R_RemoveExtPtrWeakRef_direct
  Referenced from: /Users/duncan/GitWorkingArea/XML/testRemoveFinalizers.so
  Expected in: flat namespace
 in /Users/duncan/GitWorkingArea/XML/testRemoveFinalizers.so
