Delete in lieu of truncate?
Logically a truncate and a delete statement are very similar. They work a little different which allows truncate to be faster in many cases. For the specific code in question, it might be a little slower but it should perform the same purpose and the code should work fine.

However, if your site lacks the ability to TRUNCATE then it also lacks the ability to DROP tables. It's possible to run Drupal on sites like that for very specific purposes, but there are several Drupal features that will not work without the ability to DROP tables.