gfx_setbgpal

From ArchaicPixels: HuC and PCEAS Documentation

gfx_setbgpal(char bgcolor);      [ 3.04+ ]

    Set default BG palette group to bgcolor.
    Used by gfx_init().

    Example: 'gfx_setbgpal(5)' before gfx_init() will cause the gfx_*()
             functions to use the BG palette entries from $50 through $5F