* Change: In Hurricane::SharedPath, the hash for the shared pathes, which
    serves for Map<> storing, were computed "on the fly" at each
    ::getHash() call, and were involving recursive calls of all the
    hashes along the components of the shared path. This is terribly
    slow especially in a design with a deep hierarchy (typical case
    LS180).
      Now, at the cost of one supplemenental unsigned long in each
    SharedPath, it is only computed once in the constructor, and is
    no longer recursive (only access the *first* tail, if any).
      As a consequence, the re-display computation delay becomes
    bearable. But also speed up any transhierarchical walkthough.

* Change: In Etesianengine::toHurricane(), no longer call interTies().
    This *should* no longer be needed as almost all standard cells
    (SxLib & FlexLib) already contains polarisation contacts.
      So do not need to disturb the placement.
      Secondly, in presence of a H-Tree, when there is not enough
    space to insert a sufficient number of tie cell, the lefmost one
    in the sub-row is shifted to left, overlaping the H-Tree buffer
    cells. This is a bug (even signaled by a warning). But as this
    part is disabled, I won't correct it soon...

* Change: In Cumulus/plugins.block.Block, for standalone block,
    the external Pin where created non-square, the "perpandicular"
    side made a half wire width. But in case the wire width was an
    odd number of physical grid, it was leading to offgrid screaming
    in the GDS driver.
      Now, just make them square...

Fix Coriolis build on Arch Linux

See merge request vlsi-eda/coriolis!7

* Bug: In CRL::GdsDriver::GdsStream::operator<<(Cell*), when looking for
    layer names ending with ".pin", must also check that the string is
    at least 4 characters long.

Signed-off-by: Myrtle Shah <gatecat@chipflow.io>

Signed-off-by: Myrtle Shah <gatecat@chipflow.io>

The CMake version set was so old that obsolete policies were being
enabled and breaking FindPython. 2.8 should still be old enough not to
cause problems for any current users.

Signed-off-by: Myrtle Shah <gatecat@chipflow.io>

This field has been deprecated in Python 3 and no longer exists at all
in Python 3.9, causing a build error.

Signed-off-by: Myrtle Shah <gatecat@chipflow.io>

Signed-off-by: gatecat <gatecat@ds0.me>

* Bug: In KatanaEngine::annotateGlobalGraph(), the minimum track reservation
    was not applied correctly. Instead of adding the *difference* between
    the minimum and the current reservation, the minimum was simply added.
    Leading to too high reservation. And loss of control about what we
    were doing on the edges capacities...
      Really stupid.

    large enough instead of creating one big via along the horizontal
    cell power lines, we create one big VIA at each end. To avoid to
    create too massive obstructions.
      But the thresold was too high for cmos45, leading to short with
    the clock tree trunk.

* Change: In bootstrap/coriolisEnv.py, when all tries to locate the
    installation root in predefined locations, try the directory the
    script is installed in.
      This allows for a user to use an installation made in another
    user's account.

* Bug: In Anabatic::_desaturate(), the set of invalidated GCells was never
    cleared between iterations of desaturated GCells. This was not a
    memory leak per se because, in the end, the set was freed. But it did
    induce a gigantic bloating in memory. This finally explain the strange
    slow down in that stage.
      Detected in ls180+cmos45.
* Change: In Anabatic::GCell, add a flag for each depth to avoid
    desaturating twice the same GCell (maybe not needed now that the
    bug is corrected, but it ensure a no-looping).

* Bug: In cumulus/plugins.block.configuration.GaugeConf.expandMinArea(),
    The minimal length of the segment intermediate wires where computed
    for the minimal area using an integer division ( // ), which is
    stupid for less than 1.0 values. They are real quantities at this
    point...
      This was making the DRC of ls180 failing.

Note: We don't suppress warnings due to unused variables or functions,
      as we may need them later or in debug mode...

* Change: In Hurricane::DBo::~DBo, add a noexcept(false) because
    constructed by default destructor of derived classes seems to
    loosen it. The right solution whould be to explicitely define
    all virtual destructors (too lazy for now).
* Change: In Viewer::Script, replace the deprecated
    PyModule_GetFilename() by PyModule_GetFilenameObject(), Unicode
    support again...

* Change: In bootstrap/coriolisEnv.py, the script was looking to
    pythonX.Y (like "python2.7" or "python3.6") only. Now added
    "major" only directories like "python2" or "python3".