smokeqt 4.9.90-1 is not built with $RPM_OPT_FLAGS:
4.9.4-1 doesn't have this problem:
Hrm, seems I totally missed seeing this bug until now. Fix looks good, thanks!
* Mon Feb 25 2013 Rex Dieter <firstname.lastname@example.org> 4.10.0-2
- don't override CXXFLAGS (#884836, kde#315772)