is a style bug at best. When the variable isn't a flag, it potentially
overflows after a large number of settings. Here the number of settings
is limited by ARG_MAX, but the variable is the exit code so it became
bogus after the second setting and effectively overflowed to 0 after
approx. 128 settings.
Fixed some style bugs involving comments in and near previous commit.
Clarification of previous commit message: df -t didn't give undefined
behaviour, and the behaviour used to conform perfectly with the man
page, since the buggy behaviour is documented in the BUGS section. -t
just worked when no files or file systems were specified, and was just
ignored if a file or file system was specified.
1181cb31e7