[MacPorts] #59834: Boost: update to 1.76.0

[MacPorts]

#59834: Boost: update to 1.76.0
------------------------+-----------------------
  Reporter:  michaelld  |      Owner:  michaelld
      Type:  update     |     Status:  assigned
  Priority:  Normal     |  Milestone:
 Component:  ports      |    Version:
Resolution:             |   Keywords:
      Port:  boost      |
------------------------+-----------------------

Comment (by mascguy):

 The new version will be wholly segregated, allowing it to be installed
 side-by-side with our current version. It'll require a bit of work, but no
 big deal.

 That approach will allow us to support as many versions as desired, with
 no conflicts. And ports can depend on whichever version they need.

-- 
Ticket URL: <https://trac.macports.org/ticket/59834#comment:18>
MacPorts <https://www.macports.org/>
Ports system for macOS