Merge branch 'script'

* script: (25 commits)
  script: add note to BUGS man page section
  script: fix EOF problems
  script: improve poll debugging
  script: cleanup signals usage
  script: debug poll() results
  script: add support for SCRIPT_DEBUG=
  script: remove magic constants from poll code
  script: rename control struct members
  script: close timingfp also when -e
  tests: add scriptreplay test
  script: move timing file opening close to use of it
  script: add noreturn function attributes
  script: use gettime_monotonic() to get timing file timestamps
  script: use correct input type, move comment, and so on
  script: replace strftime() workaround with CFLAGS = -Wno-format-y2k
  script: move do_io() content to small functions
  script: add 'Script started' line always to capture file
  script: remove io vs signal race
  script: merge doinput() and output() functions to do_io()
  script: use poll() rather than select()
  ...