[MacPorts] #69719: draco @1.5.7: error: no type named 'invoke_result' in namespace 'std'

[MacPorts]

#69719: draco @1.5.7: error: no type named 'invoke_result' in namespace 'std'
----------------------+------------------------
  Reporter:  Nicob73  |      Owner:  nilason
      Type:  defect   |     Status:  reopened
  Priority:  Normal   |  Milestone:
 Component:  ports    |    Version:  2.9.3
Resolution:           |   Keywords:  highsierra
      Port:  draco    |
----------------------+------------------------

Comment (by nilason):

 Replying to [comment:8 ryandesign]:
 > Specifying the C++17 requirement is necessary but not sufficient to
 resolve the problem. When the Xcode version of clang doesn't support C++17
 this will make MacPorts choose a MacPorts version of clang, which will
 then fail to build due to https://github.com/google/draco/issues/1058.

 Thanks! [https://github.com/macports/macports-ports/pull/23516 PR23516]
 will hopefully address this, I'm not absolutely certain it will work for
 older systems with gcc though (not sure what linker they use).

-- 
Ticket URL: <https://trac.macports.org/ticket/69719#comment:9>
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