[MacPorts] #47811: boost: use system layout instead of tagged layout

[MacPorts]

#47811: boost: use system layout instead of tagged layout
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  Reporter:  mjpost@…     |      Owner:  ryandesign@…
      Type:  enhancement  |     Status:  new
  Priority:  Normal       |  Milestone:
 Component:  ports        |    Version:  2.3.3
Resolution:               |   Keywords:
      Port:  boost        |
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Comment (by ryandesign@…):

 Replying to [comment:4 mjpost@…]:
 > Yes, with my change, you'd only be able to have a single version of the
 libraries installed at a time (at least, under /opt/local/{lib,include}).

 More than that: we would not be able to give the user the option to change
 their boost installation in any way. If we were to implement your proposed
 change where e.g. libboost_program_options.dylib is the multi-threaded
 library, then we would not be able to give the user an option that would
 cause libboost_program_options.dylib to be the single-threaded library,
 because that would break any other ports in MacPorts that link with that
 library, because those other ports could have been built on our automated
 build server which would have boost installed in its default configuration
 (i.e. per your proposal libboost_program_options.dylib would default to
 being multi-threaded).

 Again, if nobody would ever want to use the single-threaded libraries,
 then we could make this change. And that's a possiblity: as you mentioned,
 the only way currently to get MacPorts to build the single-threaded
 libraries is to deactivate the no_single variant which is on by default.
 Since our build server only builds default variants, and since the
 MacPorts dependency engine does not have the ability to declare
 dependencies on variants of a port, there is probably no port in MacPorts
 today that requires the single-threaded boost libraries. But it's possible
 some user has software built outside of MacPorts that uses MacPorts
 boost's single-threaded libraries.

 It would probably be a lot of work to make this change, for a small gain
 in convenience and a small gain in simplifying the port. But the way the
 boost port currently works predates me taking over as its maintainer so
 I'm not totally informed on the reasons for it working the way it
 currently does and am therefore reluctant to make major changes.

-- 
Ticket URL: <https://trac.macports.org/ticket/47811#comment:5>
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