The Apache mod_perl coding style document says this
Whenever you create a list or an array, always add a comma after the last item. The reason for doing this is that it's highly probable that new items will be appended to the end of the list in the future. If the comma is missing and this isn't noticed, there will be an error.
What your manager may have been thinking of is that doing the same thing in C is non-standard and non-portable, however there is no excuse for his extraordinary behaviour.
