NAME
	LockLayerRom -- Lock Layer structure by ROM(gfx lib) code.

   SYNOPSIS
	LockLayerRom( layer )
		       a5

	void LockLayerRom( struct Layer * );

   FUNCTION
	Return when the layer is locked and no other task may
	alter the ClipRect structure in the Layer structure.
	This call does not destroy any registers.
	This call nests so that callers in this chain will not lock
	themselves out.
	Do not have the Layer locked during a call to intuition.
	There is a potential deadlock problem here, if intuition
	needs to get other locks as well.
	Having the layer locked prevents other tasks from using the
	layer library functions, most notably intuition itself. So
	be brief.
	layers.library's LockLayer is identical to LockLayerRom.

   INPUTS
	layer - pointer to Layer structure

   RESULTS
	The layer is locked and the task can render assuming the
	ClipRects will not change out from underneath it until
	an UnlockLayerRom is called.

   SEE ALSO
	UnlockLayerRom() layers.library/LockLayer() graphics/clip.h