old_contents: import os
  import sys
  
  env = os.environ
  env['LD_PRELOAD'] = os.path.join(os.path.dirname(os.path.realpath(__file__)), 'lib_mtrace')
  
  os.execve(sys.argv[1], sys.argv[2:], env)
  
  
new_contents: import os
  import sys
  
  env = os.environ
  env['LD_PRELOAD'] = os.path.join(os.path.dirname(os.path.realpath(__file__)), 'lib_mtrace')
  
  os.execve(sys.argv[1], sys.argv[1:], env)
  
subject: fix arg parsing error