QtScript does not compile

In file included from /Users/ziller/git/qt/5.9/src/qtscript/src/script/api/qscriptable.h:27:
In file included from /Users/ziller/git/qt/5.9/build/qtbase/include/QtCore/qobjectdefs.h:1:
In file included from /Users/ziller/git/qt/5.9/build/qtbase/include/QtCore/../../../../src/qtbase/src/corelib/kernel/qobjectdefs.h:48:
In file included from /Users/ziller/git/qt/5.9/build/qtbase/include/QtCore/qnamespace.h:1:
In file included from /Users/ziller/git/qt/5.9/build/qtbase/include/QtCore/../../../../src/qtbase/src/corelib/global/qnamespace.h:43:
In file included from /Users/ziller/git/qt/5.9/build/qtbase/include/QtCore/qglobal.h:1:
/Users/ziller/git/qt/5.9/build/qtbase/include/QtCore/../../../../src/qtbase/src/corelib/global/qglobal.h:788:1: error: use of the 'nodiscard' attribute is a C++1z extension [-Werror,-Wc++1z-extensions]
Q_REQUIRED_RESULT Q_DECL_CONSTEXPR static inline Q_DECL_UNUSED bool qFuzzyIsNull(double d)
^
/Users/ziller/git/qt/5.9/build/qtbase/include/QtCore/../../../../src/qtbase/src/corelib/global/qcompilerdetection.h:1177:31: note: expanded from macro 'Q_REQUIRED_RESULT'
#  define Q_REQUIRED_RESULT [[nodiscard]]

/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang++ -c -pipe -stdlib=libc++ -fno-strict-aliasing -O2 -std=c++1y -fapplication-extension  -arch x86_64 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.12.sdk -mmacosx-version-min=10.10 -fvisibility=hidden -fvisibility-inlines-hidden -fno-exceptions -fPIC -DQT_NO_FOREACH -DJSC=QTJSC -Djscyyparse=qtjscyyparse -Djscyylex=qtjscyylex -Djscyyerror=qtjscyyerror -DWTF=QTWTF -DQT_NO_USING_NAMESPACE -DQLALR_NO_QSCRIPTGRAMMAR_DEBUG_INFO -DBUILDING_QT__=1 -DWTF_USE_ACCELERATED_COMPOSITING -DNDEBUG -DENABLE_JSC_MULTIPLE_THREADS=0 -DLOG_DISABLED=1 -DBUILDING_QT__ -DBUILDING_JavaScriptCore -DBUILDING_WTF -DWTF_USE_JAVASCRIPTCORE_BINDINGS=1 -DWTF_CHANGES=1 -DJS_NO_EXPORT -DQT_NO_NARROWING_CONVERSIONS_IN_CONNECT -DQT_BUILD_SCRIPT_LIB -DQT_BUILDING_QT -DQT_NO_CAST_TO_ASCII -DQT_ASCII_CAST_WARNINGS -DQT_MOC_COMPAT -DQT_USE_QSTRINGBUILDER -DQT_DEPRECATED_WARNINGS -DQT_DISABLE_DEPRECATED_BEFORE=0x050000 -DQT_NO_EXCEPTIONS -D_LARGEFILE64_SOURCE -D_LARGEFILE_SOURCE -DQT_NO_DEBUG -DQT_CORE_LIB -Wall -Wextra -Werror -Woverloaded-virtual -Wshadow -Wundef -Wfloat-equal -Wnon-virtual-dtor -Wpointer-arith -Wformat-security -Wno-long-long -Wno-variadic-macros -pedantic-errors -Wchar-subscripts -Wold-style-cast -Wcast-align -I/Users/ziller/git/qt/5.9/src/qtscript/src/script -I. -I/Users/ziller/git/qt/5.9/src/qtscript/src/3rdparty/javascriptcore/JavaScriptCore -I/Users/ziller/git/qt/5.9/src/qtscript/src/3rdparty/javascriptcore -I/Users/ziller/git/qt/5.9/src/qtscript/src/3rdparty/javascriptcore/JavaScriptCore/assembler -I/Users/ziller/git/qt/5.9/src/qtscript/src/3rdparty/javascriptcore/JavaScriptCore/bytecode -I/Users/ziller/git/qt/5.9/src/qtscript/src/3rdparty/javascriptcore/JavaScriptCore/bytecompiler -I/Users/ziller/git/qt/5.9/src/qtscript/src/3rdparty/javascriptcore/JavaScriptCore/debugger -I/Users/ziller/git/qt/5.9/src/qtscript/src/3rdparty/javascriptcore/JavaScriptCore/interpreter -I/Users/ziller/git/qt/5.9/src/qtscript/src/3rdparty/javascriptcore/JavaScriptCore/jit -I/Users/ziller/git/qt/5.9/src/qtscript/src/3rdparty/javascriptcore/JavaScriptCore/parser -I/Users/ziller/git/qt/5.9/src/qtscript/src/3rdparty/javascriptcore/JavaScriptCore/pcre -I/Users/ziller/git/qt/5.9/src/qtscript/src/3rdparty/javascriptcore/JavaScriptCore/profiler -I/Users/ziller/git/qt/5.9/src/qtscript/src/3rdparty/javascriptcore/JavaScriptCore/runtime -I/Users/ziller/git/qt/5.9/src/qtscript/src/3rdparty/javascriptcore/JavaScriptCore/wrec -I/Users/ziller/git/qt/5.9/src/qtscript/src/3rdparty/javascriptcore/JavaScriptCore/wtf -I/Users/ziller/git/qt/5.9/src/qtscript/src/3rdparty/javascriptcore/JavaScriptCore/wtf/symbian -I/Users/ziller/git/qt/5.9/src/qtscript/src/3rdparty/javascriptcore/JavaScriptCore/wtf/unicode -I/Users/ziller/git/qt/5.9/src/qtscript/src/3rdparty/javascriptcore/JavaScriptCore/yarr -I/Users/ziller/git/qt/5.9/src/qtscript/src/3rdparty/javascriptcore/JavaScriptCore/API -I/Users/ziller/git/qt/5.9/src/qtscript/src/3rdparty/javascriptcore/JavaScriptCore/ForwardingHeaders -I/Users/ziller/git/qt/5.9/src/qtscript/src/3rdparty/javascriptcore/JavaScriptCore/generated -I/Users/ziller/git/qt/5.9/src/qtscript/src/3rdparty/javascriptcore/WebKit/qt/Api -I/Users/ziller/git/qt/5.9/src/qtscript/src/3rdparty/javascriptcore/JavaScriptCore/pcre -I/Users/ziller/git/qt/5.9/src/qtscript/src/3rdparty/javascriptcore/JavaScriptCore/tmp -I/Users/ziller/git/qt/5.9/src/qtscript/src/script -I/Users/ziller/git/qt/5.9/src/qtscript/src/script/parser -I/Users/ziller/git/qt/5.9/build/qtbase/include -I/Users/ziller/git/qt/5.9/build/qtbase/include/QtScript -I/Users/ziller/git/qt/5.9/build/qtbase/include/QtScript/5.9.2 -I/Users/ziller/git/qt/5.9/build/qtbase/include/QtScript/5.9.2/QtScript -I/Users/ziller/git/qt/5.9/build/qtbase/include/QtCore/5.9.2 -I/Users/ziller/git/qt/5.9/build/qtbase/include/QtCore/5.9.2/QtCore -I/Users/ziller/git/qt/5.9/build/qtbase/include/QtCore -I.moc/release -I/Users/ziller/git/qt/5.9/src/qtbase/mkspecs/macx-clang -F/Users/ziller/git/qt/5.9/build/qtbase/lib -DQT_NO_CAST_TO_ASCII=1 -DQT_NO_CAST_FROM_ASCII=1 -UQT_RESTRICTED_CAST_FROM_ASCII -DQT_STRICT_ITERATORS -DQT_NO_URL_CAST_FROM_STRING=1 -DQT_NO_CAST_FROM_BYTEARRAY=1 -DQT_NO_KEYWORDS=1 -DQT_USE_QSTRINGBUILDER -DQT_USE_FAST_OPERATOR_PLUS -Dsignals=int -Dslots=int -Demit=public: -Dforeach=public: -Dforever=public: -xc++ /Users/ziller/git/qt/5.9/src/qtscript/src/script/api/qscriptable.h -o obj/release/release/header_qscriptable.o