Defaults qmake behavior is to make all project RPATHDIR paths absolute prior
passing them to linker. We need to make an exception for paths starting with @
such as @executable_path (Apple platforms) or $ such as $ORIGIN (Linux).
Task-number: QTBUG-31814
Change-Id: Ie9887c0046c5030c4128dda945b491a5d389ba34
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Reviewed-by: Jake Petroules <jake.petroules@petroules.com>