[MacPorts] #56294: boost: update to 1.70.0

[MacPorts]

#56294: boost: update to 1.70.0
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  Reporter:  michaelld  |      Owner:  ryandesign
      Type:  update     |     Status:  assigned
  Priority:  Normal     |  Milestone:
 Component:  ports      |    Version:
Resolution:             |   Keywords:  haspatch maintainer
      Port:  boost      |
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Comment (by michaelld):

 1.70.0 provides a CMake scripts for Boost detection using modern
 targets(any of 1.67-1.69 might have also; I don't recall seeing these
 being installed by default, but who knows). There are multiple scripts per
 Boost component .. so a -ton- of these.

 I'm having (an) issue/s getting them to work; not sure what's going on
 yet, hence the "(an)".

 This detection is kinda critical for -lots- of ports, so it needs solid
 testing / fixing if necessary ... that or we just don't install the CMake
 scripts & use the (meh) one provided by CMake itself.

 Once the CMake detection is worked out, my hope is to work on a testing /
 verification script that iterates over all of the ports that depend on
 Boost && tests each in turn all the way through "install" && tallies the
 successes and failures in some reasonable way.

-- 
Ticket URL: <https://trac.macports.org/ticket/56294#comment:22>
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