mount.zfs is called by convention (and util-linux) with arguments
last, i.e.
% mount.zfs <dataset> <mountpoint> -o <options>
This is not a problem on glibc since GNU getopt(3) will reorder the
arguments. However, alternative libc such as musl libc (or glibc with
$POSIXLY_CORRECT set) will not permute argv and fail to parse the -o
<options>. Use getopt_long so musl will permute arguments.
Signed-off-by: Christian Neukirchen <chneukirchen@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#4222