Add subdir-objects option to automake files

Fixes warnings with automake 1.14.1
Revert "Add subdir-objects option to automake files"

This reverts commit d4c84310e7bfbdb1b7d9e0cb2ab71898ce85c470.

Building fails with those options, needs more work ...
Make subdir-objects option as global default

Fixes warnings with automake 1.14.1 and still builds and
runs full testsuite (successfully). Fingers crossed for
builds with older automake...
Fix DragStats.hasBounds return type (#43198)
Revert "Fix DragStats.hasBounds return type (#43198)"

This reverts commit ace2e81f36f6c4d266e0c63a1c95cc23d3d45567.
The change was bogus, a boost::optional cannot be used like that
Merge remote-tracking branch 'gnu/master'