Log Message:
Update to 3.0.5.

Qt 3.0.5 is a bugfix release. It maintains both forward and backward
compatibility (source and binary) with Qt 3.0.4.

To avoid problems with loading plugins which link against different Qt
libraries, the semantics of plugin loading has been changed.

While I'm here add the PTHREAD_OPTS+=require thing to the buildlink files.

TODO: check qt3-{tools,docs} wrt buildlink2.