Mirror of the preceding fast-import sweep. anonymize_blob() writes
strbuf.len (size_t) into its out-parameter, and export_blob()'s
non-anonymize branch reads odb_read_object()'s size_t out-parameter
through a size_st + cast_size_t_to_ulong() bridge into an unsigned
long local; both have been silent on Windows past 4 GiB. Widen the
helper signature and the local, and drop the bridge.
check_object_signature() and parse_object_buffer() still take
unsigned long, so the silent narrowing on Windows just moves from
the local assignment to those call sites; both are separate topics.
Assisted-by: Opus 4.7
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
7e8239d95b