Merge branch 'nd/large-blobs'

Teach a few codepaths to punt (instead of dying) when large blobs that would not fit in core are involved in the operation. * nd/large-blobs: diff: shortcut for diff'ing two binary SHA-1 objects diff --stat: mark any file larger than core.bigfilethreshold binary diff.c: allow to pass more flags to diff_populate_filespec sha1_file.c: do not die failing to malloc in unpack_compressed_entry wrapper.c: introduce gentle xmallocz that does not die()