(mempool): Just free any buffer prior to reuse. Don't bother with realloc.
(flag_single_step): New function.
(skip_message): Detect "helpful" Windows CE messages and skip sending them to
the host.
(wait_for_debug_event): Use skip_message to avoid sending debug messages to the
host.
(dispatch): Prelimary implementation of single step detection.
* wince.c: Rework SH single stepping code to be more consistent with other
wince targets.
(handle_output_debug_string): Allow first chance exceptions to come through
since they seem to be all that we get on some versions of Windows CE.
(check_for_step): New function, conditionally compiled based on target.
(regptr): Delete obsolete function.
(handle_exception): Detect illegal instructions.
(get_child_debug_event): Return success only if event code matches target.
(child_create_inferior): Reflect change to get_child_debug_event arguments.
