[m-rev.] diff: simplify the creation of .int files a bit

[Zoltan Somogyi]

I intend to replace the code affected by this soon, but it is easier
for both me and for the future reviewer of that upcoming change
if the base of comparison is cleaner.

Zoltan.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Log.feb6
Type: application/octet-stream
Size: 721 bytes
Desc: not available
URL: <http://lists.mercurylang.org/archives/reviews/attachments/20190206/2e27630e/attachment-0002.obj>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: DIFF.feb6
Type: application/octet-stream
Size: 33253 bytes
Desc: not available
URL: <http://lists.mercurylang.org/archives/reviews/attachments/20190206/2e27630e/attachment-0003.obj>