main/libxml2: fix CVE-2020-24977
patch CVE-2020-24977 from upstream https://gitlab.gnome.org/GNOME/libxml2/-/commit/8e7c20a1af8776677d7890f30b7a180567701a49
Edited by slimm609
patch CVE-2020-24977 from upstream https://gitlab.gnome.org/GNOME/libxml2/-/commit/8e7c20a1af8776677d7890f30b7a180567701a49