RFC: ABI break

[Petr Salinger]

> > Just now, there is some ABI skew, exposed in libqt3-mt.
> 
> Btw, I haven't been able to determine the offending code.  Any idea why gdb
> (freebsd-gdb) fails to print a backtrace?  Could be some stack corruption
> issue?

Can you please retest again with latest glibc-2.3-head ?

I have kfreebsd system without monitor, with remote X forwarding over ssh.
In this configuration konsole from fresh chroot looks fine. 
I tested with glibc 2.3.5-9 + rev 951 + patch from rev 960.

> > Since there are no redefinition of syscalls, structures passed between 
> > kernel space and user space should be compatible.
> 
> Are you sure? 

No. Look at diff of sys/sys/ and sys/i386/include/ 
between 5.4 and 6.0 will tell more.
 
> They could keep the same struct name, but different content.
> We've seen upstream break ABI in insane ways like that before.

I would expect they change struct and redefine syscall in the same time.
Otherwise there is no way for upgrade in place.

Petr