lib/gdb.exp: Don't loop infinitly on download attempts

[Stan Shebs]

   Date: Fri, 08 Oct 1999 11:58:50 +1000
   From: Andrew Cagney <ac131313@cygnus.com>

   > I think the right thing to do is to start the countdown in gdb_load
   > and then count down/fail on the error returns in gdb_run_cmd rather
   > than the continues.

   Unfortunatly, what I saw was the testsuite repeatedly trying ``jump
   *_start'' from within that expect statement.  The expect never
   terminated and gdb_run_cmd never returned.

Actually, this may be only indirectly related to loading.

   The other options are to eliminate the exp_continue and replace the
   entire thing with a loop.  Counters on each expect statement may also be
   applicable - two ``jump *'' attempts are illegal while N of something
   else are valid.

The structure of this bit is really strange - I had to go back and
look at the Expect book, and I'm still not 100% sure of what's going
on.  exp_continue restarts matching, which is fine, and we're inside
an expect statement, which is fine, but we've done another send in
between the first match and the exp_continue - so what does the
restarted matching see exactly?  If we need to do retries, I'd rather
write each one as a separate expect statement, rather than be punished
for trying to get too clever with expect's pattern matching.

								Stan