(inode_format, show_all_fs, show_local_fs,

(inode_format, show_all_fs, show_local_fs,
show_listed_fs, posix_format, require_sync, print_type,
selected_fstype, excluded_fstype, show_dev, show_point, main):
Use bool for booleans.
(df_readable, show_dev): Use UINTMAX_MAX instead of -1.
(show_dev, show_point, main):
Use EXIT_SUCCESS/EXIT_FAILURE instead of 0/1.
Don't assume disk name lengths are <= INT_MAX.
Rewrite pct calculation to avoid cast.
(show_point): Don't assume resolved length is <= SSIZE_MAX.