/* Find the white-space-separated options specified by OPTIONS, and
using BUF to store copies of these options, set ARGV[0], ARGV[1],
etc. to the option copies. Return the number N of options found.
/* Find the white-space-separated options specified by OPTIONS, and
using BUF to store copies of these options, set ARGV[0], ARGV[1],
etc. to the option copies. Return the number N of options found.