* Bug: In Cumulus, in ClockTree.py, do not use "tie_x0" which is 2 pitch
wide to fill the free space left by clock-tree removed (unused)
buffers. If the buffer size width is odd (in pitch), it will left
a gap in the WELL. That was the cause of DRC notch errors.
Instead use "rowend_x0" which is one pitch wide.
Should use the same mechanism as in Mauka InsertFeed.