render: implement a vulkan renderer

src/compositor.rs

@@ -39,6 +39,7 @@ use {
     },
     ahash::AHashSet,
     forker::ForkerProxy,
+    jay_config::video::GfxApi,
     std::{cell::Cell, env, future::Future, ops::Deref, rc::Rc, sync::Arc, time::Duration},
     thiserror::Error,
     uapi::c,
@@ -197,6 +198,7 @@ fn start_compositor2(
         render_ctx_watchers: Default::default(),
         workspace_watchers: Default::default(),
         default_workspace_capture: Cell::new(true),
+        default_gfx_api: Cell::new(GfxApi::OpenGl),
     });
     state.tracker.register(ClientId::from_raw(0));
     create_dummy_output(&state);