new do-while syntax

[rogerson]

	Actor, an OOPS programming language for Microsoft Windows, uses
	the following construct for controlling loops:

		loop
		  ...
		while ( )
		  ...
		endloop

	To get the normal while-do or do-while it would look like:
		loop while ( )  /* while - do */
		  ...
		endloop
	and
		loop 		/* do - while */
		  ...
		while ( )
		endloop

	This is much more readable then the proposed C version, but then
	it would be incompatible with current C.

	A simple solution to the problem is to use a for statement and
	a break statement.  This is like Modula II which has the
	LOOP-EXIT-END control statement.

	-----Dale
		Rogerson-----