Variable QMAKE_CXX.COMPILER_MACROS is not defined.

[JaiSimha369]

I am trying to build Qt OpenSource for i.MX6 Integrity RTOS, as per https://doc.qt.io/qt-5/integrity-building-qt-for-imx6quad-board.html this document. but when i am trying to build getting one error
qt5/qtbase/mkspecs/features/toolchain.prf:215: Variable QMAKE_CXX.COMPILER_MACROS is not defined
Building Qt5.9 Ubuntu 16.04

can anyone help me to fix this error ?