Add y flag and environment variable LS_SAMESORT to specify the same
sorting order for time and name with the -t option.  IEEE Std 1003.2
(POSIX.2) mandates that the -t option sort in descending order, and
that if two files have the same timestamp, they should be sorted in
ascending order of their names.  The -r flag reverses both of these
sort orders, so they're never the same.  This creates significant
problems for sequentially named files stored on FAT file systems,
where it can be impossible to list them in the order in which they
were created.

Add , (comma) option to print file sizes grouped and separated by
thousands using the non-monetary separator returned by localeconv(3),
typically a comma or period.