Merge branch 'js/pack-objects-mutex-init-fix' into maint

A mutex used in "git pack-objects" were not correctly initialized and this caused "git repack" to dump core on Windows. * js/pack-objects-mutex-init-fix: pack-objects (mingw): initialize `packing_data` mutex in the correct spot pack-objects (mingw): demonstrate a segmentation fault with large deltas pack-objects: fix typo 'detla' -> 'delta'