frotz is quite portable and is divided into 'common' and os-specific files.
The common files are included here with minimal modifications. For the
os-specific files I have started with dumbfrotz, the port intended for a plain
C stdio system - it has its own screen buffering which is needed for rockbox.

Things that work
----------------

Games, mostly! If the game is too large to fit in the plugin buffer it will
stop playback and steal the audio buffer.

Saving and restoring (/path/to/story.sav, no filename selection).

Transcripts, command records and replays (likewise).

Undo, up to the limit of available memory (the rest of the plugin buffer if
the game fit there, or the rest of the audio buffer if not).

Timed input, though it resets the timer when you enter the menu and only
counts until you enter the keyboard.

Input line preloading, though the actual displayed line after editing looks
wrong.

Things that don't work because I've not implemented it
------------------------------------------------------

Reading buttons that don't appear on the rockbox keyboard.

Audible beeps (just a splash for now).

Setting the random seed.

Things which don't work in the original frotz anyway
----------------------------------------------------

Mouse and menus.

Pictures.

Non-beep sound samples.

Unicode.

Colours.
