CMake: Split and refactor QtSetup.cmake

Split all code in QtSetup into separate functions and macros, put them
in more appropriate files, and call them in
qt_internal_setup_build_and_global_variables.

A new QtBuildOptionsHelpers.cmake is created which takes care of
computing the default values of user-customizable options that are not
pure configure features, like the cmake build type, whether to build
tests / examples, whether to enable ccache, etc.

The new function calls added in
qt_internal_setup_build_and_global_variables
try to preserve the previous code flow when QtBuild was included
in-between the code that was run in QtSetup.

Macros that have dependencies on various global variables were marked
as such with inline comments for easier navigation and comprehension.

After this change, QtSetup.cmake just includes QtBuild.cmake. We leave
it to exist for easier git blaming, but new code should not be added
to it unless really necessary.

The intent is to merge a variant of this change to 6.6 and 6.5 as
well.

Task-number: QTBUG-86035
Change-Id: I3409c2d3ea8ee19a69104b12ab2692966ba5f9cf
Reviewed-by: Alexey Edelev <alexey.edelev@qt.io>

0 files changed, 0 insertions, 0 deletions