Final sanity pass: xdev

[John Hein]

Julian Elischer wrote at 18:26 -0700 on Mar 18, 2009:
 > John Hein wrote:
 > > Perhaps we should consider setting UNAME_r in the environment when
 > > building across major OS levels (possibly outside the scope of
 > > /usr/src/Makefile*).
 > > 
 > > At a certain point in the cross-arch / cross-major-OS-version building
 > > dance, we could also just say it's not supported and let people work
 > > it out with a native "same major" OS level build machine (possibly a
 > > virtual machine).
 > 
 > we also have this problem when running a different revision of
 > software in a Jail. Possibly it should be possible to set the value 
 > that uname responds with for a process and its' children, (even more 
 > so that the environment variables)
 > I'd like to be able to label a jail as a 7.1 jail on an 8.0 machine..
 > 
 > The problem in using teh single environment variable UNAME_r
 > or friends is that  the intermediate tools ARE running on a
 > different environment than the final tools so one value may not be
 > correct everywhere.
 > we sort of need one value of UNAME_r up until teh tools are built, and 
 > then another value for teh binary build. But even that may be not 
 > general enough.

In our locally grown build env, that's pretty easy to do (pass
different UNAME_r at different build stages).  Perhaps you could even
put it into the default env for a build chroot/jail (via login.conf).

As I said, it's probably not in the scope of /usr/src/Makefile*, but
because we can pass in UNAME_r from a higher level having
Makefile.inc1 use 'uname -r' for OSREL (as it is currently named) in
cross builds seems okay to me.