gammaray fails to build with Qt 5.12

| /home/sapiippo/development/yocto/pyro/build-apalis-imx6/tmp/work/cortexa9hf-neon-poky-linux-gnueabi/gammaray/5.11+gitAUTOINC+3a35d9ec64-r0/git/plugins/qmlsupport/qmlcontextpropertyadaptor.cpp: In member function 'virtual void GammaRay::QmlContextPropertyAdaptor::doSetObject(const GammaRay::ObjectInstance&)':
| /home/sapiippo/development/yocto/pyro/build-apalis-imx6/tmp/work/cortexa9hf-neon-poky-linux-gnueabi/gammaray/5.11+gitAUTOINC+3a35d9ec64-r0/git/plugins/qmlsupport/qmlcontextpropertyadaptor.cpp:103:16: error: could not convert 'e->QV4::IdentifierHashEntry::identifier' from 'QV4::PropertyKey' to 'bool'
| if (e->identifier)
| ~~~^~~~~~~~~~
| /home/sapiippo/development/yocto/pyro/build-apalis-imx6/tmp/work/cortexa9hf-neon-poky-linux-gnueabi/gammaray/5.11+gitAUTOINC+3a35d9ec64-r0/git/plugins/qmlsupport/qmlcontextpropertyadaptor.cpp:104:59: error: base operand of '->' has non-pointer type 'QV4::PropertyKey'
| m_contextPropertyNames.push_back(e->identifier->string);
| ^~
| At global scope:
| cc1plus: warning: unrecognized command line option '-Wno-c++1z-extensions'
| plugins/qmlsupport/CMakeFiles/gammaray_qmlsupport.dir/build.make:166: recipe for target 'plugins/qmlsupport/CMakeFiles/gammaray_qmlsupport.dir/qmlcontextpropertyadaptor.cpp.o' failed
| make[2]: *** [plugins/qmlsupport/CMakeFiles/gammaray_qmlsupport.dir/qmlcontextpropertyadaptor.cpp.o] Error 1
| make[2]: *** Waiting for unfinished jobs....
| /home/sapiippo/development/yocto/pyro/build-apalis-imx6/tmp/work/cortexa9hf-neon-poky-linux-gnueabi/gammaray/5.11+gitAUTOINC+3a35d9ec64-r0/git/plugins/qmlsupport/qmlbindingprovider.cpp: In member function 'void GammaRay::QmlBindingProvider::fetchSourceLocationFor(GammaRay::BindingNode*, QQmlBinding*) const':
| /home/sapiippo/development/yocto/pyro/build-apalis-imx6/tmp/work/cortexa9hf-neon-poky-linux-gnueabi/gammaray/5.11+gitAUTOINC+3a35d9ec64-r0/git/plugins/qmlsupport/qmlbindingprovider.cpp:72:28: error: variable 'QQmlSourceLocation loc' has initializer but incomplete type
| QQmlSourceLocation loc = function->sourceLocation();
| ^~~
| /home/sapiippo/development/yocto/pyro/build-apalis-imx6/tmp/work/cortexa9hf-neon-poky-linux-gnueabi/gammaray/5.11+gitAUTOINC+3a35d9ec64-r0/git/plugins/qmlsupport/qmlbindingprovider.cpp:72:59: error: invalid use of incomplete type 'struct QQmlSourceLocation'
| QQmlSourceLocation loc = function->sourceLocation();
| ^
| ERROR: oe_runmake failed