[MacPorts] #59834: Boost: update to 1.74.0

[MacPorts]

#59834: Boost: update to 1.74.0
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  Reporter:  michaelld  |      Owner:  (none)
      Type:  update     |     Status:  new
  Priority:  Normal     |  Milestone:
 Component:  ports      |    Version:
Resolution:             |   Keywords:
      Port:  boost      |
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Comment (by michaelld):

 Thanks for the prod, @mascguy!

 Boost is a challenging port to get updated. The API changes regularly
 which breaks backwards compatibility. It takes time even for actively-in-
 development ports to get working with these releases; and older ports that
 are not actively in development will just fail eventually because the
 Boost API is so different. We can't just update the "boost" port because
 it breaks other ports; reliably; potentially for weeks if not months until
 fixes are in place. Some ports will of course work without modification;
 but many will not. Some of those ports are not trivially updated to work
 with newer Boost, whether by us directly or via upstream fixes. These
 reasons are why Boost is stuck where it is for such a long time. Prior PRs
 have failed because too many ports could not be updated, and it would take
 too much aggregate time to do all of this work -- and so some of the ports
 updated in the PR get stale & need to be rebased, which takes even more
 time ... just not enough time in the day / week / month to get all of this
 done!

 The best solution I've been able to come up with -- and, this is imperfect
 -- is to use the current "boost_169" port or create some more recent
 version such as "boost_172" as the dependency instead of "boost" on -all-
 dependent ports. Then, we can update the boost port to the current release
 without worrying about breaking ports that use it. Ports that are able to
 use the "boost" current release port can change the dependency to allow
 for either of those Boost ports; but, at least one version of Boost should
 be tested to always work ... which is why this solution is imperfect! What
 happens if some future port that uses Boost can't work with 1.69 or the
 current release? I guess we'll need intermediate ports such as "boost_174"
 etc ... which so long as they can be built and installed in parallel could
 be made to work. Not a perfect solution, but at least the vast majority of
 ports that depend on Boost would work regardless of the Boost release port
 version and compatibility.

-- 
Ticket URL: <https://trac.macports.org/ticket/59834#comment:9>
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