[MacPorts] #54798: webkit2-gtk +quartz build fails with many compiler errors

[MacPorts]

#54798: webkit2-gtk +quartz build fails with many compiler errors
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  Reporter:  Polyergic    |      Owner:  jeremyhu
      Type:  defect       |     Status:  assigned
  Priority:  Normal       |  Milestone:
 Component:  ports        |    Version:
Resolution:               |   Keywords:
      Port:  webkit2-gtk  |
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Comment (by kencu):

 Ah. A more appropriate fix is this:
 {{{
 configure.cxxflags-append -std=c++14
 }}}
 which, when added to the `webkit2-gtk @2.14.2` portfile, fixes the build
 using the system clang on Sierra (and maybe some of those other previous
 clangs that wouldn't build it as well).

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Ticket URL: <https://trac.macports.org/ticket/54798#comment:5>
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