Necessitas: dynamic_cast_will_always_fail / How to set QMAKE_CXXFLAGS

[sedi]

Hi, I have set up Necessitas Qt Creator (2.3.1) for Android and I am able to create some little programs.
With my project I get this error message:

C:\qtOnAndroid\Kombiversuch-build--Necessitas_Qt_4_8_0_for_Android_armv5_Release\..\. .\necessitas\Android\Qt\480\armeabi\include\QtCore \qglobal.h:2481: error: 'dynamic_cast_will_always_fail_because_rtti_is_dis abled' is not a member of 'QPushButton*'

I've googled heavily: BogDan himself states, that exceptions and rtti are disabled by default - but they can be switched on with

QMAKE_CXXFLAGS += -fexceptions -frtti

QMAKE_CXXFLAGS += -fexceptions -frtti

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He points to a website for further reading, but I can't see how and where to set the CXXFLAGS, they are not mentioned on that page.

I've tried adding this line at the beginning of my .pro-file (nothing changes, same error message).

Then I've tried giving it as a parameter to qmake in Projects|BuildSteps|qmake|Details in the "additional arguments" line.
This threw the error message:

***Unknown option -fexceptions
The process "c:\necessitas\android\qt\480\armeabi\bin\qmake.ex e" exited with code 1.

I am aware that I am obviously lacking very basic knowledge about the build process in QtCreator. So please excuse my questions:

1. How can I set these two flags
2. Where can I read more to understand the build process better?

I'd gratefully appreciate any help on this!