It is a dependency for qmake and qtpaths. If neither of them are
built, because building tools might be disabled, skip building the
library as well.
Task-number: QTBUG-127334
Change-Id: I0f7d5bc9d9a4539a6d25f7c2d841e9b8978a83a3
Reviewed-by: Alexey Edelev <alexey.edelev@qt.io>
(cherry picked from commit 82b2c51c3aec148c890d732978ca4a881e5c6f82)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>