can not step

[Ilya N. Golubev]

Versions: 6.3, 6.5.

System: i686-pc-linux-gnu.  Packages:

kernel-2.6.3.27mdk-1-1mdk
glibc-2.3.3-12.8.100mdk
gcc-3.3.2-6mdk

Built emacs 21.4a with that gcc, `CFLAGS=-g -O2'.  Stopped in
`decode_coding_iso2022', which does no system calls, consists entirely
of cpu use.  All attempts to step further would fail.  `step', `next',
`stepi' would behave exactly like `continue'.

Observed that only on system with set of packages as above, and even
there only with that debugged program.