I have QMAKE_CXXFLAGS += "-include myglobal.h" in my .pro file. The file myglobal.h itself contains some global defines and inline Qt code. With Qt 5.3 compilation works fine. With 5.4 it fails with the eror:
The problem is in Makefile in compiling QRC file.
With Qt 5.3 the resource file has been compiled with rcc, and then with gcc $(CXXFLAGS) $(INCFLAGS).
With Qt 5.4 gcc is called without $(INCPATH), as a result Qt includes are not available, and gcc fails.