buildsystem - add an uninstall target

uses the KDE extra-cmake-module ECMUninstallTarget.cmake

cmake/ECM/modules/ECMUninstallTarget.cmake

@@ -0,0 +1,50 @@
+#.rst:
+# ECMUninstallTarget
+# ------------------
+#
+# Add an ``uninstall`` target.
+#
+# By including this module, an ``uninstall`` target will be added to your CMake
+# project. This will remove all files installed (or updated) by a previous
+# invocation of the ``install`` target. It will not remove files created or
+# modified by an ``install(SCRIPT)`` or ``install(CODE)`` command; you should
+# create a custom uninstallation target for these and use ``add_dependency`` to
+# make the ``uninstall`` target depend on it:
+#
+# .. code-block:: cmake
+#
+#   include(ECMUninstallTarget)
+#   install(SCRIPT install-foo.cmake)
+#   add_custom_target(uninstall_foo COMMAND ${CMAKE_COMMAND} -P uninstall-foo.cmake)
+#   add_dependency(uninstall uninstall_foo)
+#
+# The target will fail if the ``install`` target has not yet been run (so it is
+# not possible to run CMake on the project and then immediately run the
+# ``uninstall`` target).
+#
+# .. warning::
+#
+#   CMake deliberately does not provide an ``uninstall`` target by default on
+#   the basis that such a target has the potential to remove important files
+#   from a user's computer. Use with caution.
+#
+# Since 1.7.0.
+
+#=============================================================================
+# SPDX-FileCopyrightText: 2015 Alex Merry <alex.merry@kde.org>
+#
+# SPDX-License-Identifier: BSD-3-Clause
+
+if (NOT TARGET uninstall)
+    configure_file(
+        "${CMAKE_CURRENT_LIST_DIR}/ecm_uninstall.cmake.in"
+        "${CMAKE_BINARY_DIR}/ecm_uninstall.cmake"
+        IMMEDIATE
+        @ONLY
+    )
+
+    add_custom_target(uninstall
+        COMMAND "${CMAKE_COMMAND}" -P "${CMAKE_BINARY_DIR}/ecm_uninstall.cmake"
+        WORKING_DIRECTORY "${CMAKE_BINARY_DIR}"
+    )
+endif()