In ancient times, the existence of QMAKE_RUN_CXX_IMP determined the
use of implicit rules. The code path for implicit rules was turned
off in 2006 (0287fe3c), which probably was a refactoring artifact.
Later, implicit rules were enabled again using a different approach.
These days, the non-existence of QMAKE_RUN_CXX determines the use of
implicit rules.
We remove the dead code path now and rely on the latter condition.
One part of the dead code is a feature that turns off inference rules if
the OBJECTS_DIR is set or source file names do not match expectations.
If somebody ever missed this, it has been reimplemented otherwise.
Or not.
Change-Id: If3ce9904d9c1df6e4048c58c2452854cce7fa206
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>
bbb40616d2