QWT was bumped to 6.0 and qgis is currently incompatible with the new version. In order to update qwt, we will have to drop qgis into the aur.
I have looked into patching qgis to be compatible with qwt 6. I managed to get an initial patch accepted, but there is a lot more work to be done, on code that I'm unfamiliar with. upstream bug report: http://hub.qgis.org/issues/3562 -Thomas Dziedzic
