[MacPorts] #61921: qt5-qtwebengine @5.15.2: does not build on macOS 10.13 with Xcode 9

[MacPorts]

#61921: qt5-qtwebengine @5.15.2: does not build on macOS 10.13 with Xcode 9
------------------------------+------------------------
  Reporter:  dliessi          |      Owner:  (none)
      Type:  defect           |     Status:  new
  Priority:  Normal           |  Milestone:
 Component:  ports            |    Version:
Resolution:                   |   Keywords:  highsierra
      Port:  qt5-qtwebengine  |
------------------------------+------------------------

Comment (by kencu):

 Well, somewhat surprisingly perhaps, using macports-clang-9.0 does indeed
 let you past the configure stage. So at least that works.

 The next error seems to be this somewhat messy construction:
 {{{
 :info:build /bin/sh: ../../../../../../../../../../bin/clang++: No such
 file or directory
 }}}

 We are attempting (perhaps fruitlessly) to use macports-clang-9.0, but qt
 has configured for this odd compiler spec, which I assume was supposed to
 be the Xcode clang++.

 So -- either give up and move up to Xcode10 (that's my recommendation, and
 that is what I did) or -- would have to see how to make the build actually
 use macports-clang-9.0 during the build itself, not just during the
 configure phase.

 Somewhere there is some script that is assuming that on MacOS, only the
 Xcode clang is going to be used here, and so that script did not
 anticipate the idea of ever using a different, specified compiler on
 MacOS.

 Finding that exact bit of code buried in qt5-qtwebengine might prove to be
 a trick, but you might simply grep the source for something that would be
 {{{/bin/clang}}} or {{{/bin/clang++}}}.

 Grepping for {{{/bin/clang++}}} might prove difficult with those {{{++}}}
 signs, and I'd have to monkey around a while to see how to do that best.

 Marcus also writes the recommended qt5 compiler spec into the qt5/qmake5
 portgroups, and also into the build scripts that installed with
 qt5-qttools, so it could be passed into the qt5-qtwebengine build from
 there.

-- 
Ticket URL: <https://trac.macports.org/ticket/61921#comment:4>
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