QLayoutPolicy: fix annoying -Wdeprecated-enum-enum-conversion

Says GCC -std=c++20:

    src/gui/util/qlayoutpolicy_p.h:127:30: warning: bitwise operation between different enumeration types ‘QLayoutPolicy::Policy’ and ‘QLayoutPolicy::PolicyFlag’ is deprecated [-Wdeprecated-enum-enum-conversion]
      127 |         if (verticalPolicy() & ExpandFlag)
          |             ~~~~~~~~~~~~~~~~~^~~~~~~~~~~~

Fix by making Policy a QFlags<PolicyFlag>, which we can do because the
class is private. In QSizePolicy, this would break BC.

Since a QFlags cannot be opened for constants like an enum, we need to
define the ex-Policy-enumerators as static inline constexpr objects
instead.

Pick-to: 6.2
Change-Id: I29bc938f86508deed3f99ad9d1c1892547206c05
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

0 files changed, 0 insertions, 0 deletions