Hello Daniel,

  re: http://www.sourceware.org/ml/gdb/2006-08/msg00079.html

Would the attached patch fix your problem?

2006-08-09  Joel Brobecker  <brobecker@adacore.com>

        * gdb.base/step-bt.exp: Make hexadecimal address option in
        expected output of the backtrace commands.

Tested on x86-linux, no regression.

Thanks,
-- 
Joel