Add CMake support

tests/blackgui/CMakeLists.txt

@@ -0,0 +1,10 @@
+# SPDX-FileCopyrightText: Copyright (C) swift Project Community / Contributors
+# SPDX-License-Identifier: GPL-3.0-or-later OR LicenseRef-swift-pilot-client-1
+
+include(${PROJECT_SOURCE_DIR}/cmake/swift_test.cmake)
+
+add_swift_test(
+        NAME gui_guiutility
+        SOURCES testguiutility/testguiutility.cpp testguiutility/testguiutility.h
+        LINK_LIBRARIES gui tests_test Qt::Core
+)