Import version 458 of "less". Changes since version 444:
* Allow backslash escaping of metacharacters in LESS environment variable
  after the --use-backslash option.
* Don't quit if syntax errors are found in command line options.
* Increase sizes of some internal buffers.
* Fix configure bug with --with-regex=none.
* Fix crash with "stty rows 0".
* Fix display bug when using up/down arrow on the command line.
* Add ESC-F command to keep reading data until a pattern is found.
* Use exit code of LESSOPEN script if LESSOPEN starts with "||".
* When up/down arrow is used on the command line immediately after
  typing text, the next command starting with that text is found.
* Add support for GNU regex.
* Add configure option --with-regex=none and fix compile errors
  when compiling with no regex library.
* Fix possible crashes caused by malformed LESSOPEN or
  LESSCLOSE variables.
* Fix bug highlighting text which is discontiguous in the file
  due to backspace processing.
* Fix bug in displaying status column when scrolling backwards
  with -J and -S in effect.