How to fix this in 5.1-REL??

[walt]

Brooks Davis answered:

walt asked:
>>What does 'buildworld' give us that the new kernel might need?

> The correct toolchain including the compiler and config(8).

Okay, thanks, that helps.

Just thinking out loud about worst-case examples for people who
do routinely use 'make world' (like I have for several years).

I found out first-hand why installworld quits halfway through
when the new executables won't run on the old kernel.  I need no
further education on that point ;-)

I'm thinking, though, that doing 'make kernel' first has a much
lower potential for disaster than 'make world':  if I reboot after
a 'make kernel' and the new kernel won't run on the old world, then
all I need to do to recover is to boot the old kernel again and
'make buildworld'. Seems difficult to do any real harm this way.

Is this completely wrong-headed?  Am I missing something important?

(Yes, I know I should just do it the right way every time -- but
I'm trying to reason through just why some ways are right and
some are wrong.)

Thanks for any insights.