[MacPorts] #70077: The stub PG should (be able to) clear all pre- and post- blocks

[MacPorts]

#70077: The stub PG should (be able to) clear all pre- and post- blocks
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 Reporter:  RJVB    |      Owner:  (none)
     Type:  defect  |     Status:  new
 Priority:  Normal  |  Milestone:
Component:  base    |    Version:
 Keywords:          |       Port:
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 Anyone who has ever had to deal with the situation where a port is (or has
 to be) nothing but a stub knows that it can get unnecessarily complicated
 to implement. The `stub` PG helps but not with the fact that `pre-X` and
 `post-X` code blocks will be executed anyway.

 I don't really know what's the ideal solution here, clearing all those
 pre- and post- blocks from the stub PortGroup or simply not executing them
 under specific condition(s). The stub PG currently uses a `post-destroot`
 block itself but that could just as well be used as the `destroot`
 instead.

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Ticket URL: <https://trac.macports.org/ticket/70077>
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