Commit: Close memory leaks in chew

[Nick Clifton]

Hi Andreas,

>> -  free (buffer->ptr);
>> +  if (buffer->ptr)
>> +    free (buffer->ptr);
> 
> free (0) is a no-op.

OK - I will remember that for the future.  I doubt if it really matters
here, since the performance penalty of the test is trivial.

Cheers
  Nick