the extraction, especially for routines like ExtFindNeighbors where
it was previously not handled at all. A new method was introduced
in which split tiles with neither side TT_SPACE will get an extra
allocated structure that contains pointers to two regions representing
the nodes on the tile's left and right sides, independently. The fix
(as yet not fully tested) should resolve problems with extracting the
sky130 I/O cells, which contain a FET with 45 degree angles on the
gate, where a split tile is divided between the gate and the source or
drain, and therefore represents two different nodes. Also, there were
extraction errors related to incorrect handling of split tiles having
only one node, where a split tile became connected to the wrong node.
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