Notes:
- 'check_status_re' and therefore 'runpipe_re' use 'grep -E'
instead of 'grep' in order to simplify regexp that
contains >=2 digit exit statuses.
NOTE: Formally speaking this breaks backward compatibility.
- If PIPESTATUS_VERBOSE variable is set to non-empty string, then
check_status0 and check_status_re functions print an error
message to stderr.
Changes: