NAME
        UnlockLayers -- Unlock all layers from graphics output.
                        Restart graphics output to layers that have been waiting
    SYNOPSIS
        UnlockLayers( li )
                      a0
        void UnlockLayers( struct layer_info *);
    FUNCTION
        Make all layers in this layer list unlocked.
        Then call unlocklayerinfo
    INPUTS
        li - pointer to the layer_info structure
    BUGS
    SEE ALSO
        locklayers(), unlocklayer(), graphics/layers.h