[MacPorts] #59780: cmake fails to build on Leopard 10.5: error: 'shared_mutex' is unavailable: introduced in macOS 10.12

[MacPorts]

#59780: cmake fails to build on Leopard 10.5: error: 'shared_mutex' is unavailable:
introduced in macOS 10.12
-----------------------+-----------------------
  Reporter:  rmottola  |      Owner:  michaelld
      Type:  defect    |     Status:  assigned
  Priority:  Normal    |  Milestone:
 Component:  ports     |    Version:
Resolution:            |   Keywords:  leopard
      Port:  cmake     |
-----------------------+-----------------------

Comment (by kencu):

 I think it has something to do with the {{{__config}}} header in the
 clang-7.0 libc++ headers. The availability is probably not set right for
 the new libcxx I install on Leopard i386.

 I fixed that in newer clangs, but I think I never got around to backdating
 that fix to clang-7.0.

 see <https://github.com/macports/macports-
 ports/blob/master/lang/llvm-9.0/files/5005-MacPorts-only-patch-libcxx-
 includes-disable-availability-tests.diff>.

-- 
Ticket URL: <https://trac.macports.org/ticket/59780#comment:11>
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