[MacPorts] #55639: QtCore unusable with Apple LLVM version 9.0.0

[MacPorts]

#55639: QtCore unusable with Apple LLVM version 9.0.0
-----------------------+------------------------
  Reporter:  janstary  |      Owner:  easieste@…
      Type:  defect    |     Status:  assigned
  Priority:  Normal    |  Milestone:
 Component:  ports     |    Version:  2.4.99
Resolution:            |   Keywords:
      Port:  bitcoin   |
-----------------------+------------------------

Comment (by MarcusCalhoun-Lopez):

 Replying to [comment:1 ryandesign]:
 > Marcus, any idea why Qt would be claiming that a recent clang is not
 C++11 capable?
 This does not seem to be a Qt issue.[[BR]]
 The configure script for bitcoin adds {{{-std=c++11}}} the the c++
 compiler name ('''not''' the C++ compiler flags).[[BR]]
 It then uses the same compiler name for both C++ and Objective-C++ but
 '''only''' if OBJCXX is undefined.[[BR]]
 MacPorts, however defines OBJCXX.[[BR]]
 In the configure.ac file, there is the following comment
 {{{
 dnl Unless the user specified OBJCXX, force it to be the same as CXX. This
 ensures
 dnl that we get the same -std flags for both.
 }}}
 To make matters even stranger, the C++ and Objective-C++ flags are
 '''always''' the same.[[BR]]
 In the configure.ac file:
 {{{
 OBJCXXFLAGS="$CXXFLAGS"
 }}}

 There seem to be two options:
 1. Do not define OBJCXX so that the configure script figures it out for
 itself: {{{configure.objcxx}}}
 1. Manually do what the configure script does: {{{configure.objcxx-append
 -std=c++11}}}

 We could also modify {{{configure.cxxflags}}}, but this would mean
 {{{-std=c++11}}} would be added twice for the C++ compiler.

--
Ticket URL: <https://trac.macports.org/ticket/55639#comment:3>
MacPorts <https://www.macports.org/>
Ports system for macOS