apitrace: AutoMoc: Error: moc predefs generation command failed

https://github.com/apitrace/apitrace/blob/65d2605/gui/CMakeLists.txt#L74

Generating MOC predefs moc_predefs.h
AutoMoc: Error: moc predefs generation command failed
AutoMoc: Command:
/usr/bin/c++ -dM -E -c /usr/share/cmake-3.9/Modules/CMakeCXXCompilerABI.cpp -I/tmp/tmp.cU62V3fLK5/src/apitrace-7.1/build/gui -I/tmp/tmp.cU62V3fLK5/src/apitrace-7.1/gui -I/tmp/tmp.cU62V3fLK5/src/apitrace-7.1/build/gui/qapitrace_autogen/include -I/tmp/tmp.cU62V3fLK5/src/apitrace-7.1/thirdparty/khronos -I/tmp/tmp.cU62V3fLK5/src/apitrace-7.1/thirdparty/snappy -I/tmp/tmp.cU62V3fLK5/src/apitrace-7.1/thirdparty/libbacktrace -I/tmp/tmp.cU62V3fLK5/src/apitrace-7.1/thirdparty/gtest/include -I/tmp/tmp.cU62V3fLK5/src/apitrace-7.1/common -I/tmp/tmp.cU62V3fLK5/src/apitrace-7.1 -I/usr/include/qt -I/usr/include/qt/QtWidgets -I/usr/include/qt/QtGui -I/usr/include/qt/QtCore -I/usr/lib/qt/mkspecs/linux-g++ -I/usr/include/qt/QtWebKitWidgets -I/usr/include/qt/QtWebKit -I/usr/include/qt/QtNetwork -I/usr/include -DHAVE_BACKTRACE=1 -DHAVE_READPROC_H -DHAVE_X11 -DQT_CORE_LIB -DQT_FORCE_ASSERTS -DQT_GUI_LIB -DQT_NETWORK_LIB -DQT_NO_DEBUG -DQT_WEBKITWIDGETS_LIB -DQT_WEBKIT_LIB -DQT_WIDGETS_LIB -D_GNU_SOURCE -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -nn
AutoMoc: Command output:
c++: error: unrecognized command line option ‘-nn’; did you mean ‘-Qn’?

GCC 7.2.0, Qt 5.9.1