This removes support of separate qmake versions in one port: as we
discovered, there are no ports actually needing this; strangers like
print/poppler don't use qmake in build.
This should be transparent to current ports. But expect more tweaks there:
for now, qt?.port.mk forces qmake.port.mk inclusion, but that will be
reworked to a more common scheme.
Same idea from (at least) espie@ and me; also, espie@ agrees on the plan.
an opt-in. Actual qmake-based ports will be switched on case-by-case
basis in the near future.
Unslacking after discussion with at least naddy@ & espie@ from... 2014?!
Oh my.
MODQT_* values.
This makes it possible to include both qt3 and qt4, as long as one is
very careful in choosing the right variables, without any change for the
existing qt3-only, qt4-only ports.
We don't bother with qt and qt2 as they are mostly end-of-life.
