[PATCH] os: Prevent backtrace from being stopped in noreturn functions.

[Mark Kettenis]

> From: Oliver McFadden <oliver.mcfadden at nokia.com>
> Date: Mon,  1 Mar 2010 09:42:58 +0200
> 
> From: Ylimaki Rami (EXT-Vincit/Tampere) <ext-rami.ylimaki at nokia.com>
> 
> There are two noreturn functions in the X server: FatalError and
> AbortServer. Having any of those two functions in the middle of a call
> stack will prevent unwinding the program properly and stops the
> backtrace at those functions in gdb.

Speaking as a GDB developer here, you should really put some pressure
on the GCC developers to stop doing unhelpful optimizations like this,
instead of adding work-arounds like this.  While ARM is the most
prominent architecture affected by this, there are other architectures
where noreturn messes up the backtraces from time to time.