UPDATE: You may delete this post now.
Makefile.Debug:120: warning: overriding recipe for target `ui_mainwindow.h'
Makefile.Debug:117: warning: ignoring old recipe for target `ui_mainwindow.h'
What I have done is, I have moved mainwindow.* to a subforlder and I have created a gui.pri file:
INCLUDEPATH += $$PWD
DEPENDPATH += $$PWD
HEADERS += \
src/GUI/mainwindow.h
SOURCES += \
src/GUI/mainwindow.cpp
FORMS += \
src/GUI/mainwindow.ui
That's the only difference than the default Qt GUI project.
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