r42961: bufstart != strstart

[Andrew Dougherty]

I'm a little suspicious of the change in r42961, which essentially does

-    const char * const file_name = file->strstart;
+    const char * const file_name = Buffer_bufstart(file);

In general, I don't think bufstart is necessarily the same as strstart.  
At least some years ago it wasn't supposed to always be the same.  For 
example, if a user did a substr(), strstart might actually point somewhere 
within the buffer, not just at the start.  At least that was my 
understanding from some time ago.  I didn't create a ticket in case my 
memory was faulty or the rules have changed, but did want to ask another 
pair of eyes to check it out.

Thanks,

-- 
    Andy Dougherty		doughera at lafayette.edu