alpha c++ compiler bug (and workaround)

There is what I believe to be a bug in the DEC Alpha C++ compiler, at
least in the version at Colorado. The bug appears with declarations
like the following:

	extern void pcaw_EnterPar( class Kernel *, int );

where Kernel is a not previously defined class. When Kernel later becomes
defined, it is as a separate symbol: the Kernel in the declaration above
does not match with the new definition.

The workaround is to move the declaration of Kernel outside of the
function header:

	class Kernel;
	extern void pcaw_EnterPar( Kernel *, int );

and it works.

Someone should fix the code in target/include/runtime.h which uses this
construct (for the master-slave system); I'll do it myself if I remember
(but not now).

The reason why I claim this is a bug is mostly by majority vote: all
other compilers seem to grok it. The devil only knows what the alleged
draft standard says.