Description of externally used routines:
	(Not including routines in RITS.C)

file I/O:
	Files are represented by integers or pointers, returned by
	the various open routines.  These routines must return
	the constant OPENLOSS when a file cannot be opened.

	cputc (c, f)		output the character c; '\n' implies
				end of line
	c = cgetc (f)		input a character; '\n' implies end
				of line; and negative or zero must be
				returned on end-of-file
	b = ceof (f)		return TRUE iff end-of-file (last
				character read by cgetc was negative
				or zero)
	gets (buffer)		read a line of characters from standard
				input into the buffer, terminated by
				NUL
	ungetc (c, f)		push back character onto input stream;
				capacity of 1 character is required
	cclose (f)		close file
	cisfd (f)		return nonzero if f looks like it is
				a file descriptor
	setprompt (s)		make string s the default prompt for
				terminal input (optional, of course)

Standard files:
	cin			standard input (used for terminal input)
	cout			standard output (used for messages)
	cerr			standard error (used for some fatal errors)

String routines:
	n = slen (s)		return length of string
	b = stcmp (s1, s2)	compare for equality of strings
	stcpy (s, d)		copy string from s to d

Storage allocation:
	*i = salloc (n)		return n integers [check for storage full]
	*c = calloc (n)		return n characters [check for storage full]
	sfree (*i)		return integers allocated by salloc
	cfree (*c)		return characters allocated by calloc
	n = alocstat (*p, *q)	return number of free words of storage
				set *p to size of free space (in words)
				 and *q to the number of free blocks
				return -1 if no stats available
Miscellaneous:
	stkdmp (f)		dump stack frames on file for debugging (optional)
	i = cputm ()		return cpu time in 1/60 sec