CMake: Integrate init-repository with the configure script

Calling configure will now implicitly run init-repository when
appropriate. See further down below for what "appropriate" means.

All supported init-repository options can be passed to configure as
except for -mirror, -oslo, -berlin.

This includes useful options like -submodules, -no-resolve-deps and
-no-optional-deps.

When running configure on a qt5.git clone without any submodules
cloned, configure will exit with a helpful error message suggesting to
pass -init-submodules, so it automatically clones missing repositories.
This means cloning is opt-in, so that internet access is not done
implicitly.

The error message also suggests passing the -submodules option.
This will affect which submodules will be cloned by init-repository
and which submodules will be configured by configure.
In this case -submodules is effectively an alias of
init-repository's -module-subset for cloning purposes.

When calling configure a second time, without -init-submodules, on an
already configured repo, init-repository behavior is entirely skipped.

-submodules now accepts init-repository-style special values like
"essential", "addon", "all", "existing", "-deprecated" for the purpose
of cloning submodules. The values are then translated into actual repos
that should also be configured or skipped by configure.

The default subset of cloned submodules is currently the same one as
init-repository, "default", which clones 44 actively maintained
repositories as well as deprecated submodules.

If configure is called a second time WITH -init-submodules, it's the
same as calling init-repository --force to re-initialize submodules.
In this case passing something like
 --submodules existing,<additional-submodules>
might make sense to add or remove submodules.

As a drive-by this also fixes the bug where you couldn't pass a
  configure -- -DFOO=0
parameter to configure, because it got treated as '0>', redirecting
from a different stream than stdout, leading to empty content in the
file.

[ChangeLog][General][Build System] The configure script now implicitly
calls init-repository when appropriate and accepts init-repository
command line options.

Fixes: QTBUG-120030
Task-number: QTBUG-122622
Change-Id: Iedbfcbf0a87c8ee89e40d00b6377b68296a65a62
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>

cmake/QtTopLevelHelpers.cmake

@@ -1,6 +1,58 @@
 # Copyright (C) 2024 The Qt Company Ltd.
 # SPDX-License-Identifier: BSD-3-Clause
 
+macro(qt_tl_include_all_helpers)
+    include(QtIRHelpers)
+    qt_ir_include_all_helpers()
+endmacro()
+
+function(qt_tl_run_toplevel_configure top_level_src_path)
+    # Filter out init-repository specific arguments before passing them to
+    # configure.
+    qt_ir_get_args_from_optfile_configure_filtered("${OPTFILE}" configure_args)
+
+    # Get the path to the qtbase configure script.
+    set(qtbase_dir_name "qtbase")
+    set(configure_path "${top_level_src_path}/${qtbase_dir_name}/configure")
+    if(CMAKE_HOST_WIN32)
+        string(APPEND configure_path ".bat")
+    endif()
+
+    if(NOT EXISTS "${configure_path}")
+        message(FATAL_ERROR
+            "The required qtbase/configure script was not found: ${configure_path}\n"
+            "Try re-running configure with --init-submodules")
+    endif()
+
+    # Make a build directory for qtbase in the current build directory.
+    set(qtbase_build_dir "${CMAKE_CURRENT_BINARY_DIR}/${qtbase_dir_name}")
+    file(MAKE_DIRECTORY "${qtbase_build_dir}")
+
+    qt_ir_execute_process_and_log_and_handle_error(
+        COMMAND_ARGS "${configure_path}" -top-level ${configure_args}
+        WORKING_DIRECTORY "${qtbase_build_dir}"
+        FORCE_VERBOSE
+    )
+endfunction()
+
+function(qt_tl_run_main_script)
+    if(NOT TOP_LEVEL_SRC_PATH)
+        message(FATAL_ERROR "Assertion: configure TOP_LEVEL_SRC_PATH is not set")
+    endif()
+
+    # Tell init-repository it is called from configure.
+    qt_ir_set_option_value(from-configure TRUE)
+
+    # Run init-repository in-process.
+    qt_ir_run_main_script("${TOP_LEVEL_SRC_PATH}" exit_reason)
+    if(exit_reason AND NOT exit_reason STREQUAL "ALREADY_INITIALIZED")
+        return()
+    endif()
+
+    # Then run configure out-of-process.
+    qt_tl_run_toplevel_configure("${TOP_LEVEL_SRC_PATH}")
+endfunction()
+
 # Populates $out_module_list with all subdirectories that have a CMakeLists.txt file
 function(qt_internal_find_modules out_module_list)
     set(module_list "")