Configurable HBLANK/VBLANK generator

[sy2002]

Each core is supposed to deliver these signals to the M2M framework:

      -- Video output
      video_ce_o              : out std_logic;
      video_ce_ovl_o          : out std_logic;
      video_red_o             : out std_logic_vector(7 downto 0);
      video_green_o           : out std_logic_vector(7 downto 0);
      video_blue_o            : out std_logic_vector(7 downto 0);
      video_vs_o              : out std_logic;
      video_hs_o              : out std_logic;
      video_hblank_o          : out std_logic;
      video_vblank_o          : out std_logic;

But what does one do, if the core does not deliver any HBLANK/VBLANK signals?

For example: ZX-Uno:
https://github.com/sy2002/zxuno4mega65/blob/dev-M2M/CORE/vhdl/main.vhd#L115

It only outputs HSYNC/VSYNC but no HBLANK/VBLANK.

How can we make the life of people who port cores as simple as possible when it comes to this topic?