Log Message:
glibmm2.68: updated to 2.68.2

2.68.2 (stable):

Glib:
* Replace all g_quark_from_static_string() by g_quark_from_string()

Gio:
* FileEnumerator: Remove refreturn to avoid memory leak
* ListModel::get_object(): Make it work for interface classes
* AppInfo::get_all(): Avoid a crash on Windows

Build:
* MSVC build: Remove extraneous GLIBMM_API in Glib::ustring