Compiling opencv with qt support (linux)

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I followed the instructions page to download opencv3 source and installed with default settings. I assumed this would by default compile with qt support. But this doesn't seem to be the case as seen by the following error: OpenCV Error: The function/feature is not implemented (The library is compiled without QT support) in createButton

This question suggests the WITH_QT flag but I'm not sure where to set that. Moreover, when I run cv::getBuildInformation() as suggested in that question, this is some of the output I get. A couple of things I have noticed is:

QT 5.x:                      YES (ver 5.5.1)
QT OpenGL support:           NO
OpenGL support:              NO
VTK support:                 YES (ver 6.2.0)

Install path: /opt/ros/kinetic

but this is not the install path that I provided when I installed it. I can see it being installed in /usr/local, yet this is the output I get. I did have ROS installed separately, that also does come with opencv libraries so I'm not sure where the conflict is