*
   NAME
	AttemptLockLayerRom -- Attempt to Lock Layer structure
					 by ROM(gfx lib) code

   SYNOPSIS
	gotit = AttemptLockLayerRom( layer )
	 d0			      a5

	BOOL AttempLockLayerRom( struct Layer * );

   FUNCTION
	Query the current state of the lock on this Layer. If it is
	already locked then return FALSE, could not lock. If the
	Layer was not locked then lock it and return TRUE.
	This call does not destroy any registers.
	This call nests so that callers in this chain will not lock
	themselves out.

   INPUTS
	layer - pointer to Layer structure

   RESULT
	gotit - TRUE or FALSE depending on whether the Layer was
		successfully locked by the caller.

   SEE ALSO
	LockLayerRom() UnlockLayerRom()