* tac: correct behavior of -b option
Correct the behavior of `tac -b` to match that of GNU coreutils
`tac`. Specifically, this changes `tac -b` to assume *leading* line
separators instead of the default *trailing* line separators.
Before this commit, the (incorrect) behavior was
$ printf "/abc/def" | tac -b -s "/"
def/abc/
After this commit, the behavior is
$ printf "/abc/def" | tac -b -s "/"
/def/abc
Fixes#2262.
* fixup! tac: correct behavior of -b option
* fixup! tac: correct behavior of -b option
Co-authored-by: Sylvestre Ledru <sylvestre@debian.org>
