NAME
        ReleasePen -- Release an allocated palette entry to the free pool. (V39)


   SYNOPSIS
        ReleasePen( cm, n)
                    a0 d0

        void ReleasePen( Struct colormap *, ulong);

   FUNCTION
        Return the palette entry for use by other applications.
        If the reference count for this palette entry goes to zero,
        then it may be reset to another RGB value.

   INPUTS
       cm  =  A pointer to a color map created by getcolormap().

        n   =  A palette index obtained via any of the palette allocation
               functions. Passing a -1 will result in this call doing
               nothing.

   BUGS

   NOTES
        This function works for both shared and exclusive palette entries.

   SEE ALSO
        getcolormap() obtainpen() obtainbestpena()