rename the source to gsb_crc32.c.
This is a prerequisite of unifying kernel zlib instances.
PR: 229763
Submitted by: Yoshihiro Ota <ota at j.email.ne.jp>
Differential Revision: https://reviews.freebsd.org/D20193
ffs_subr.c requires calculate_crc32c() from libkern. Unfortunately we
cannot just add libkern/crc32.c to libstand because crc32.o is already
compiled from contrib/zlib/crc32.c. Use the include trick to rename
the source.
Note that libstand also provides crc32.c which seems to be unused.
Reviewed by: imp
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D17677