backend: set EGL_RENDERABLE_TYPE and EGL_SURFACE_TYPE

Ensure these are set to the correct value.

backend/drm/renderer.c

@@ -25,6 +25,8 @@ bool init_drm_renderer(struct wlr_drm_backend *drm,
 	}
 
 	static EGLint config_attribs[] = {
+		EGL_SURFACE_TYPE, EGL_WINDOW_BIT,
+		EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
 		EGL_RED_SIZE, 1,
 		EGL_GREEN_SIZE, 1,
 		EGL_BLUE_SIZE, 1,

backend/headless/backend.c

@@ -101,6 +101,7 @@ struct wlr_backend *wlr_headless_backend_create(struct wl_display *display,
 
 	static const EGLint config_attribs[] = {
 		EGL_SURFACE_TYPE, EGL_PBUFFER_BIT,
+		EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
 		EGL_ALPHA_SIZE, 0,
 		EGL_BLUE_SIZE, 1,
 		EGL_GREEN_SIZE, 1,

backend/wayland/backend.c

@@ -306,6 +306,7 @@ struct wlr_backend *wlr_wl_backend_create(struct wl_display *display,
 
 	static EGLint config_attribs[] = {
 		EGL_SURFACE_TYPE, EGL_WINDOW_BIT,
+		EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
 		EGL_RED_SIZE, 1,
 		EGL_GREEN_SIZE, 1,
 		EGL_BLUE_SIZE, 1,

backend/x11/backend.c

@@ -280,6 +280,7 @@ struct wlr_backend *wlr_x11_backend_create(struct wl_display *display,
 
 	static EGLint config_attribs[] = {
 		EGL_SURFACE_TYPE, EGL_WINDOW_BIT,
+		EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
 		EGL_RED_SIZE, 1,
 		EGL_GREEN_SIZE, 1,
 		EGL_BLUE_SIZE, 1,