[MacPorts] #51620: py-pyqt5: fix DBus module build and pyversion conflicts, support multiple Qt5 ports

[MacPorts]

#51620: py-pyqt5: fix DBus module build and pyversion conflicts, support multiple
Qt5 ports
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  Reporter:  RJVB         |      Owner:  mkae
      Type:  enhancement  |     Status:  assigned
  Priority:  Normal       |  Milestone:
 Component:  ports        |    Version:
Resolution:               |   Keywords:
      Port:  py-pyqt5     |
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Comment (by RJVB):

 Here's the new patch announced on #52500. It looks more complex than it is
 because I couldn't resist cleaning up whitespace inconsistencies too.

 Compared to my original submission, this patch drops the
 qt{webkit,webengine} variants which were already implemented under a
 shorter name, but also reverts to NOT making the QtWebEngine variant
 default. That Qt component is huge as said and not yet used by many ports,
 so I consider it still justified to make it available on explicit demand
 only.

 I have implemented an additional variant the interest of which became
 apparent while using the software. It prevents aborting (= on-demand
 crashing) when Python errors (even benign ones) occur.

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Ticket URL: <https://trac.macports.org/ticket/51620#comment:3>
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