To reproduce use the attached example.
Example requires ICU libs which you should download from icu-project.org and copy the libs into example's lib folder.

Also you need to set DYLD_LIBRARY_PATH that it points to example's lib folder.

If following define is used then example doesn't crash.

#ifndef Q_MOC_RUN
#include <unicode/coll.h>
#endif

Same example compiles without any issues with Qt4.x, even when Q_MOC_RUN is
not used.