4.21.0 - build: Automate copyright year management - meson-build: Add missing function checks - meson-build: Use SPDX license expression - meson-build: Add tests option - meson-build: Use 'pkgconfig_define' in dep.get_variable() - meson-build: Use 'dependencies' in cc.alignment() - meson-build: Update debug/optimization flag management - meson-build: Add missing gir prefixes - meson-build: Use path builder and fs instead of literal '/' - Add meson build - tests: Always cleanup xfconfd process - tests: Enable t-list-channels test - tests: Fix test failure because of xfconfd not running - Migrate to xdt-gen-visibility and xdt-check-abi - channel: Complete and harmonize docs of get_string_list()/get_arrayv() - channel: Warn in case of failure in get_string_list() - channel: Fix get_arrayv() return value - Translation Updates: Albanian, Slovak