Fixes <https://bugs.gnu.org/37468>.
* gnu/packages/patches/python-libxml2-utf8.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.
* gnu/packages/xml.scm (python-libxml2/fixed): New variable.
* gnu/packages/glib.scm (itstool/fixed): New variable.
* gnu/packages/gnome.scm (gnumeric)[native-inputs]: Use ITSTOOL/FIXED
instead of ITSTOOL.