find file src {string match *.o $file} {file delete $file}

Except, of course, that what you just typed wouldn't work. It would find all the object files in the src directory, but not in any of its subdirectories because it wouldn't match any of its subdirectories.

Well, again, you don't need to tell find(1) to traverse subdirs so I wasn't expecting that it needed to be explicit in this case either.   If I just wanted to do file ops within the current directory, I'd use glob and eval. :-)

Incidentally, I hope you've also twigged to the fact that modifying someone else's code in an OSS project is almost always bound to lead to a more heated discussion than if you'd actually discussed your proposed changes in advance and allowed for public comment before changing anything.  MacPorts isn't unique in this way - if you'd gone and hacked on one of *BSD or Linux's device drivers and committed the changes without saying anything first, well, let's just say this conversation would still be burning hot with lots of folks piling on.  MacPorts is small enough that this doesn't really happen yet, but the principles remain the same and once MP gets bigger, you'll see an increasing need for discussion in advance of "svn commit".