Per earlier discussions we bump the deployment target for LTS releases
and follow up by requiring the latest SDK available for building.
As layer backed views and dark mode is a lot more stable these days in
Qt and on macOS in general we no longer support the option to build with
the 10.13 SDK. A workaround in case this functionality is still needed
is to explicitly set the QMAKE_MAC_SDK_VERSION qmake variable, which
will tell the linker to write that version into the MachO header of
the executable, which will then be read by AppKit when determining
which features to opt in to.
Change-Id: Ied4f6d75b710505a5c440c990b82567bea780db6
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>
2e63d12183