make buildkernel fails without complete source tree

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John Baldwin <jhb at freebsd.org> wrote:
> Yes, but the thread started because someone installed 'ssys' and tried to
> build it using 'buildkernel' because that's what the handbook mentions.   
> In
> fact, the handbook doesn't even mention the old way anymore at all, so  
> for
> new users ssys for all intents and purposes does depend on sbase.

To my mind Handbook ('8.3 Building and Installing a Custom Kernel' and  
'21.4 Rebuilding "world"')
should contain an appropriate paragraphs from /usr/src/UPDATING with  
head-note and comments. What do you/we need two variants of docs about  
system update for? Of course one have precedence of other but maybe better  
to have one (w/o and w/ comments)?
Apropos if you/we care about clarity of Handbook, the title 'Rebuilding  
"world"' is not very clear especially for new users. (But on the other  
side maybe it makes reading not so dull?..)

About easy commands for building and installing a kernel: i think that  
'easy' kernel targets can be added to /usr/src/sys Makefile(s) and  
/usr/src Makefile(s) may refer to it.

Handbook is conflicting with /usr/src/UPDATING now:
Handbook: '21.4.14.5. How can I speed up making the world?'
'Pass the -jn option to make(1) to run multiple processes in parallel.  
This usually helps regardless of whether you have a single or a multi  
processor machine.'
UPDATING: 'Avoid using make -j when upgrading. <..>'