This is required so we can use validateflow for example
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/506>
env.set('GST_PLUGIN_SYSTEM_PATH_1_0', '')
env.set('GST_REGISTRY', '@0@/@1@.registry'.format(meson.current_build_dir(), 'validate'))
env.set('GST_PLUGIN_SCANNER_1_0', gst_scanner_dir + '/gst-plugin-scanner')
-env.set('GST_PLUGIN_LOADING_WHITELIST', 'gstreamer')
+env.set('GST_PLUGIN_LOADING_WHITELIST', 'gstreamer', 'gst-validate')
foreach t: tests
test_dir_name = t.split('/')