maint: prefer psame_inode, PSAME_INODE, STP_*

maint: prefer psame_inode, PSAME_INODE, STP_*

Prefer psame_inode, PSAME_INODE, STP_NBLOCKS, and STP_BLKSIZE,
which take addresses of objects, to their counterparts that
take the whole objects.  In some cases the whole objects might
not be initialized, which would be undefined behavior strictly
speaking.
* gl/lib/root-dev-ino.h (ROOT_DEV_INO_CHECK):
* src/cp-hash.c (src_to_dest_compare):
* src/ls.c (dev_ino_compare):
* src/pwd.c (robust_getcwd):
Prefer PSAME_INODE to SAME_INODE.
* src/chown-core.c (restricted_chown):
* src/copy.c (copy_reg, same_file_ok, source_is_dst_backup)
(copy_internal):
* src/ln.c (do_link):
* src/pwd.c (logical_getcwd):
* src/sort.c (avoid_trashing_input):
* src/split.c (create):
* src/stat.c (find_bind_mount):
Prefer psame_inode to SAME_INODE.
* src/copy.c (infer_scantype):
* src/du.c (process_file):
* src/ls.c (gobble_file, print_long_format)
(print_file_name_and_frills, length_of_file_name_and_frills):
* src/stat.c (print_stat):
Prefer STP_NBLOCKS to ST_NBLOCKS.
* src/copy.c (copy_reg):
* src/head.c (elide_tail_bytes_file, elide_tail_lines_file):
* src/ioblksize.h (io_blksize):
* src/od.c (skip):
* src/shred.c (do_wipefd):
* src/stat.c (print_stat):
* src/tail.c (tail_bytes):
* src/truncate.c (do_ftruncate):
* src/wc.c (wc):
Prefer STP_BLKSIZE to ST_BLKSIZE.
* src/ioblksize.h (io_blksize):
Arg is now struct stat const *, not struct stat.  All callers changed.