[MacPorts] #71026: shapelib @1.6.1 -- Unable to build -- fatal error: 'filesystem' file not found

[MacPorts]

#71026: shapelib @1.6.1 -- Unable to build -- fatal error: 'filesystem' file not
found
-----------------------+------------------------
  Reporter:  RobK88    |      Owner:  (none)
      Type:  defect    |     Status:  new
  Priority:  Normal    |  Milestone:
 Component:  ports     |    Version:  2.10.2
Resolution:            |   Keywords:  highsierra
      Port:  shapelib  |
-----------------------+------------------------

Comment (by kencu):

 The system software installed in High Sierra by Apple is now too old to
 support "filesystem", and no amount of tweaking the bulid or selecting
 other compilers will change that.

 If you use legacysupport and enable macports-libcxx in legacysupport's
 options for systems up to your needed system, it will often build.

 It then needs to be actually tested.

 Because the libc++ in macports-libcxx and the libc++ installed in High
 SIerra are different, and because LLVM/LIBCXX specifically provide no
 guarantees of compatibility between different libc++ versions, there are
 runtime errors that show up sometimes. If those runtime errors happen,
 then the macports-libcxx approach can't be used.

-- 
Ticket URL: <https://trac.macports.org/ticket/71026#comment:5>
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