where did cross-build customization come from ?

[Mikus Grinbergs]

FYI -- don't intend to do anything about it -- just letting you know 
I had a strange experience.

I keep both a Joyride build and an Update.1 build on my G1G1;  I 
switch between them with the 'O' button at boot.  Today I used 
'olpc-update' (from Joyride) to install the latest Update.1, then 
used 'olpc-update' (from Update.1) to install the latest Joyride.

I normally apply various customizations in /etc and in /usr (e.g., 
to disable frame "auto-raise", and to preset some environmental 
variables).  The way I remember it, having booted this latest 
Joyride build I manually edited-in my changes.  But then when I 
booted the latest Update.1 build, I found the /etc and /usr changes 
already made.

It might be Alzheimer's that is making me forget applying my changes 
twice.  But I am left with the question:  "how come my edits showed 
up with both builds, when I remember making my edits only once ?"

mikus