POSTIN

/bin/sh

update-alternatives --install /usr/bin/qmake-qt4 qmake-qt4 /usr/lib64/qt4/bin/qmake 20

POSTUN

/bin/sh

if ! [ -e /usr/lib64/qt4/bin/qmake ]; then
  update-alternatives --remove qmake-qt4 /usr/lib64/qt4/bin/qmake
fi