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

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'

diff --cc builtin/pack-objects.c
Simple merge

diff --cc pack-objects.c
Simple merge

diff --cc pack-objects.h
Simple merge