How to modify defconfig file - make savedefconfig?

[Grant Edwards <grant.b.edwards@gmail.com>]

What is the "right" way to modify a defconfig file?

Most sources I've found just say things like "edit the defconfig
file". That seems error-prone -- especially when dealing with settings
that have side effects.

I did stumble across one mention of "make savedefconfig", and this
seems to be the right way to modify a defconfig file:

    make myboard_defconfig
    make menuconfig
    make savedefconfig
    cp defconfig configs/myboard_defconfig

Do people manually edit their defconfig file when they want to make a
change, or do they use "make savedefconfig" like I show above?

One reason I'm asking is that the original defconfig file provided by
the silicon vendor (Renesas) appears to be a manually stripped-down
..config file, because when I do

   make vendors_defconfig
   make savedefconfig

The defconfig file generated by 'make savedefconfig' looks _nothing_
like the starting vendors_defconfig. The new defconfig generates the
same .config file as the vendors_defconfig file. But the
vendors_defconfig file is arranged completely differently with
different/extra comments, extra blank lines, etc.

--
Grant