MacPorts build/work directory links and TimeMachine

[René J.V. Bertin]

Hello,

For a while now I've been noticing that TimeMachine makes huge backups (hundreds of Mb) that do not seem to correspond to the total size of the files changed during the backup interval (6h for me). 
I've set to exclude most of /opt/local/var/macports (the large guys in there), but there are the symlinks to the work directories in /opt/local/var/macports/build that source builds leave behind as long as the port hasn't been cleaned.

Is it possible that TimeMachine (on OS X 10.6.8) not only backs up those symlinks but also their destination (OS X being rather adamant about "normalising" symlinks in most circumstances)? Browsing through the TM interface it seems indeed as if I end up in a (forbidden) backup of the work directory when I double-click the symlink in a port directory backup, but it is near impossible to know whether that's not simply a view on the current directory, not a backup.

Addendum: I built qt4-mac from source tonight, after creating a local version of the port directory. Sure enough this morning TM wanted to backup nearly 6Gb ...

Any thoughts?

René