this pretty surprising behavior would interfere with building the
examples from an installed qt tree with qmakes from other qt builds.
.qmake.conf (and .qmake.cache) files provide a possibility to explicitly
"anchor" project roots, so there is no point in having a second, even
more magic way to do it.
Task-number: QTBUG-35485
Change-Id: I8fd4fda67cabafdf55e7a98282dcdfaffb4a405e
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@digia.com>