[MacPorts] #50671: boost: Update to 1.64.0

[MacPorts]

#50671: boost: Update to 1.64.0
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  Reporter:  eborisch  |      Owner:  ryandesign
      Type:  update    |     Status:  new
  Priority:  Normal    |  Milestone:
 Component:  ports     |    Version:  2.3.4
Resolution:            |   Keywords:  haspatch
      Port:  boost     |
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Comment (by ryandesign):

 Replying to [comment:36 gaming-hacker]:
 > why doesn't macports create it's own github fork of boost?  create
 subtrees, apply patches, clean it up, etc. create a custom build bot and
 let the bot thrash the updates for regression testing.

 Why would we want to do that, as opposed to the method we've always used
 for incorporating patches into ports?

 If a MacPorts contributor, or anyone, wants to help develop boost, they
 can certainly do so in whatever way they want, including forking a
 repository and sending pull requests, if that's a contribution method the
 developers of boost support. But that needn't have anything to do with how
 the MacPorts boost portfile operates.

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Ticket URL: <https://trac.macports.org/ticket/50671#comment:37>
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