Helper programs

Linux/macOS helpers retain these positional arguments:

qtalh_printer host tcp_port queue_key bw|bw_bold|oki_bold|hp_color
qtalh_DB      host rpc_program_number queue_key

The printer helper reports connection/write failures on stderr, retains the current record, and retries after one second. Connections or writes with no progress time out after ten seconds. Each outage is reported once, followed by a message when delivery resumes.

Keys must match -P/-O. The database argument is an RPC program number, version 1/procedure 1, rather than a TCP port. Native System V queue layout is ABI-dependent. Mixed legacy/Qt records are limited to 250 - sizeof(long) text bytes (242 on 64-bit Linux); oversized queue records report errors without preventing file logging. Windows does not build these helpers and rejects -P/-O.