Log Message:
Update to 20181121. Changes:

- NOFIXSMTPIO: new environment variable to perform no filtering.
- FIXSMTPIODEBUG: prefix program name to log messages.
- Compile as C99.
- Have die_nomem() log two levels of call stack.
- Have get_one() log one caller further.
- Avoid extern in declarations.
- Empty next_pile and free event when done.
- Use acceptutils' stralloc wrappers in tls_info().
- Don't call tls_info(): no point setting TLS connection environment
  variables when our child has already forked.