include/opt: Don't treat options with values as arrays

include/opt: Don't treat options with values as arrays

Because the bit pattern __opt_flag_is_array has more than one set
bit, it is not enough to use a bitwise and to check if an option is
an array, but that is what `opt_print_help()' does.

This commit modifies `opt_print_help()' so that it checks whether
the result of the bitwise and equals __opt_flag_is_array, avoiding
any option with a value to be treated as an array.