Not possible to set -march option for gcc

After updating to QtCreator 4.1 i got next issue on opening my qbs file:

C:\Qt\Tools\QtCreator\share\qtcreator\qbs\share\qbs\modules\cpp\GenericGCC.qbs:197: error: The following properties have invalid values:
cpp.cxxFlags: '-target', '-triple', '-arch' and '-march' cannot appear in flags; set qbs.architecture instead

I use cpp.cxxFlags: ["-march=pentium4"].
As you see it is used not for selecting arm/x86/x86_64 as it can be done with qbs.architecture, but to change CPU minimum command set.

Is there is any workaround?