dbusmenu-qt5 build failure on 10.7 and 10.8 buildbots because of using libstdc++

[Ryan Schmidt]

> On Oct 6, 2016, at 3:56 AM, René J.V. Bertin <rjvbertin at gmail.com> wrote:
> 
> Hi,
> 
> I got the attached build failure notifications, which in both cases I think can be traced to the use of `-stdlib=libstdc++` :
> 
> {{{
> [ 84%] Building CXX object src/CMakeFiles/dbusmenu-qt5.dir/utils.cpp.o
> cd /opt/local/var/macports/build/_opt_bblocal_var_buildworker_ports_build_ports_devel_dbusmenu-qt/dbusmenu-qt5/work/build/src && /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang++   -DQT_CORE_LIB -DQT_DBUS_LIB -DQT_GUI_LIB -DQT_NO_DEBUG -DQT_WIDGETS_LIB -Ddbusmenu_qt5_EXPORTS -iframework /opt/local/libexec/qt5/lib -isystem /opt/local/libexec/qt5/lib/QtWidgets.framework/Headers -isystem /opt/local/libexec/qt5/lib/QtGui.framework/Headers -isystem /opt/local/libexec/qt5/lib/QtCore.framework/Headers -isystem /opt/local/libexec/qt5/./mkspecs/macx-clang -isystem /System/Library/Frameworks/OpenGL.framework/Headers -isystem /opt/local/libexec/qt5/lib/QtDBus.framework/Headers -I/opt/local/var/macports/build/_opt_bblocal_var_buildworker_ports_build_ports_devel_dbusmenu-qt/dbusmenu-qt5/work/libdbusmenu-qt-0.9.3.15.10/src -I/opt/local/var/macports/build/_opt_bblocal_var_buildworker_ports_build_ports_devel_dbusmenu-qt/dbusmenu-qt5/work/build/src  -pipe -Os -stdlib=libstdc++  -fvisibility=hidden -Woverloaded-virtual -Wall -std=c++11 -DNDEBUG -arch x86_64 -mmacosx-version-min=10.8 -fPIC   -fPIC -o CMakeFiles/dbusmenu-qt5.dir/utils.cpp.o -c /opt/local/var/macports/build/_opt_bblocal_var_buildworker_ports_build_ports_devel_dbusmenu-qt/dbusmenu-qt5/work/libdbusmenu-qt-0.9.3.15.10/src/utils.cpp
> In file included from /opt/local/var/macports/build/_opt_bblocal_var_buildworker_ports_build_ports_devel_dbusmenu-qt/dbusmenu-qt5/work/libdbusmenu-qt-0.9.3.15.10/src/dbusmenuexporterdbus_p.cpp:21:
> In file included from /opt/local/var/macports/build/_opt_bblocal_var_buildworker_ports_build_ports_devel_dbusmenu-qt/dbusmenu-qt5/work/libdbusmenu-qt-0.9.3.15.10/src/dbusmenuexporterdbus_p.h:25:
> In file included from /opt/local/var/macports/build/_opt_bblocal_var_buildworker_ports_build_ports_devel_dbusmenu-qt/dbusmenu-qt5/work/libdbusmenu-qt-0.9.3.15.10/src/dbusmenutypes_p.h:25:
> In file included from /opt/local/libexec/qt5/lib/QtCore.framework/Headers/QList:1:
> In file included from /opt/local/libexec/qt5/lib/QtCore.framework/Headers/qlist.h:41:
> In file included from /opt/local/libexec/qt5/lib/QtCore.framework/Headers/qhashfunctions.h:39:
> /opt/local/libexec/qt5/lib/QtCore.framework/Headers/qpair.h:62:44: error: no member named 'declval' in namespace 'std'
>        Q_DECL_NOEXCEPT_EXPR(noexcept(std::declval<T1&>() = p.first) && noexcept(std::declval<T2&>() = p.second))
>                                      ~~~~~^
> /opt/local/libexec/qt5/lib/QtCore.framework/Headers/qcompilerdetection.h:1042:43: note: expanded from macro 'Q_DECL_NOEXCEPT_EXPR'
> # define Q_DECL_NOEXCEPT_EXPR(x) noexcept(x)
> }}}
> 
> I'm a bit surprised that this happens on 10.8 . What can be done about it - include the cxx11 PortGroup or something else?

If a port requires C++11 / libc++, include the cxx11 1.0 portgroup.

Until we figure out how to prevent it, you'll still receive failure notifications from non-libc++ buildbot workers about that.