NAME
        FreeBitMap -- free a bitmap created by allocbitmap (v39)

   SYNOPSIS
        FreeBitMap(bm)
                   a0

        VOID FreeBitMap(struct bitmap *)

   FUNCTION
        Frees bitmap and all associated bitplanes

   INPUTS
        bm  =  A pointer to a bitmap structure. passing a null-pointer
               (meaning "do nothing") is OK.

   BUGS

   NOTES
        Be careful to insure that any rendering done to the bitmap has
        completed (by calling waitblit()) before you call this function.

   SEE ALSO
        allocbitmap()