[3.13] gh-126623: Update libexpat to 2.6.4, make future updates easier (GH-126792)#126796

gpshead merged 1 commit intopython:3.13python/cpython:3.13from

miss-islington:backport-3c99969-3.13miss-islington/cpython:backport-3c99969-3.13Copy head branch name to clipboard