def update_ncmds(ncmds)
      fmt = Utils.specialize_format("L=", endianness)
      ncmds_raw = [ncmds].pack(fmt)
      @raw_data[16..19] = ncmds_raw
    end
def update_ncmds(ncmds)
      fmt = Utils.specialize_format("L=", endianness)
      ncmds_raw = [ncmds].pack(fmt)
      @raw_data[16..19] = ncmds_raw
    end
Updates the number of load commands in the raw data.
 @param ncmds [Integer] the new number of commands
 @return [void]
 @api private