search install prefix for qwt correctly
libqwt.so should take precedence over libqwt-qt4.so (qwt6 vs qwt5)
workaround for broken QIcon.fromTheme missing function
remove scipy references from gr-perf-monitorx
runtime: gr-perf-monitorx, make very sure we are using the right matplotlib backend before causing any problems by defaulting to a different one
runtime: fix for gr_enabled_realtime_scheduling