Log Message:
frotz: Update to 2.51

Summary of changes between Frotz 2.50 and Frotz 2.51:
=====================================================

Frotz 2.51 was released on Wednesday February 12, 2020.

This is a minor release focusing on minor enhancements and bug fixes.

NEW FEATURES

- Added an -f option for Dumb Frotz to mark up the output with color and
  formatting codes.  Currently "irc", "ansi", and \ 
"normal" modes are
  supported.

BUG FIXES

- Cleanly account for some installations of ncurses which have the
  library split into ncurses (high level) and tinfo (low level).

- Added an idiosyncrasy fix for Cutthroats, which assumes a
  quick-and-dirty conversion of 24-hour notation to am/pm notation.

- Fixed where the Makefile used spaces instead of a tab in a rarely-used
  recipe.

- Fixed a memory allocation problem with restoring a game at the command
  line using the -L option.

- Fixed an oversight in which curses wasn't being shut down properly
  when fatal zcode errors were encountered.