Now that inputs (81152194) and outputs (3f0858ed) are explicitly set for
the preprocess stage we can enable the new build system.
Using the legacy build system will produce a build error in Xcode 13,
but the build will succeed:
error: The Legacy Build System will be removed in a future release.
You can configure the selected build system and this deprecation
message in File > Project Settings.
Fixes: QTBUG-71035
Change-Id: I108d2103872255d10de2ff5161eef892065da1c4
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
(cherry picked from commit 3d7bdf0d61699cb7fdfcef7fe7b546e3167723b2)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
a5273d4e56