Make sure helper executables used by unittests are built

E.g. tst_qprocess_and_guieventloop uses write-read-write.

This is useful e.g. when not building all of qtbase, but only a specific
unittest while hacking code.

Change-Id: Id97c6c09c180ba35554d75877a434cb258a6243d
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

tests/auto/dbus/qdbusabstractinterface/CMakeLists.txt

@@ -1,8 +1,6 @@
 # Copyright (C) 2022 The Qt Company Ltd.
 # SPDX-License-Identifier: BSD-3-Clause
 
-add_subdirectory(qpinger)
-
 qt_internal_add_test(tst_qdbusabstractinterface
     SOURCES
         interface.cpp
@@ -21,3 +19,5 @@ qt_internal_extend_target(tst_qdbusabstractinterface
         -i interface.h
 )
 
+add_subdirectory(qpinger)
+add_dependencies(tst_qdbusabstractinterface qpinger)

tests/auto/dbus/qdbusmarshall/CMakeLists.txt

@@ -4,5 +4,6 @@
 if(NOT QT_FEATURE_private_tests)
     return()
 endif()
-add_subdirectory(qpong)
 add_subdirectory(qdbusmarshall)
+add_subdirectory(qpong)
+add_dependencies(tst_qdbusmarshall qpong)

tests/auto/other/qprocess_and_guieventloop/CMakeLists.txt

@@ -12,3 +12,4 @@ qt_internal_add_test(tst_qprocess_and_guieventloop
         Qt::Gui
 )
 add_subdirectory(write-read-write)
+add_dependencies(tst_qprocess_and_guieventloop write-read-write)