compositor: Destroy renderer in weston_compositor_shutdown()

Currently we destroy the renderer before the outputs are destroyed, but
that sometimes leads to an error since a reference to the renderer is
necessary in order to destroy a gl_renderer_output.

Since destroying the renderer is common among all backends, just move
that call into weston_compositor_shutdown() immediately after the
outputs being destroyed.
diff --git a/src/compositor-drm.c b/src/compositor-drm.c
index f85298a..d637e75 100644
--- a/src/compositor-drm.c
+++ b/src/compositor-drm.c
@@ -2336,8 +2336,6 @@
 
 	destroy_sprites(d);
 
-	ec->renderer->destroy(ec);
-
 	weston_compositor_shutdown(ec);
 
 	if (d->gbm)
diff --git a/src/compositor-fbdev.c b/src/compositor-fbdev.c
index e649d43..0d96269 100644
--- a/src/compositor-fbdev.c
+++ b/src/compositor-fbdev.c
@@ -797,8 +797,6 @@
 
 	udev_input_destroy(&compositor->input);
 
-	compositor->base.renderer->destroy(&compositor->base);
-
 	/* Destroy the output. */
 	weston_compositor_shutdown(&compositor->base);
 
diff --git a/src/compositor-headless.c b/src/compositor-headless.c
index 5497455..5a5c1e6 100644
--- a/src/compositor-headless.c
+++ b/src/compositor-headless.c
@@ -141,8 +141,6 @@
 {
 	struct headless_compositor *c = (struct headless_compositor *) ec;
 
-	ec->renderer->destroy(ec);
-
 	weston_seat_release(&c->fake_seat);
 	weston_compositor_shutdown(ec);
 
diff --git a/src/compositor-rdp.c b/src/compositor-rdp.c
index 58342b9..942af50 100644
--- a/src/compositor-rdp.c
+++ b/src/compositor-rdp.c
@@ -521,7 +521,6 @@
 static void
 rdp_destroy(struct weston_compositor *ec)
 {
-	ec->renderer->destroy(ec);
 	weston_compositor_shutdown(ec);
 
 	free(ec);
diff --git a/src/compositor-rpi.c b/src/compositor-rpi.c
index 1d52a94..399090d 100644
--- a/src/compositor-rpi.c
+++ b/src/compositor-rpi.c
@@ -422,8 +422,6 @@
 
 	udev_input_destroy(&compositor->input);
 
-	compositor->base.renderer->destroy(&compositor->base);
-
 	/* destroys outputs, too */
 	weston_compositor_shutdown(&compositor->base);
 
diff --git a/src/compositor-wayland.c b/src/compositor-wayland.c
index 14ff4af..d2d8942 100644
--- a/src/compositor-wayland.c
+++ b/src/compositor-wayland.c
@@ -1398,8 +1398,6 @@
 {
 	struct wayland_compositor *c = (struct wayland_compositor *) ec;
 
-	ec->renderer->destroy(ec);
-
 	weston_compositor_shutdown(ec);
 
 	if (c->parent.shm)
diff --git a/src/compositor-x11.c b/src/compositor-x11.c
index 1b178b8..6b5eb64 100644
--- a/src/compositor-x11.c
+++ b/src/compositor-x11.c
@@ -1419,8 +1419,6 @@
 	wl_event_source_remove(compositor->xcb_source);
 	x11_input_destroy(compositor);
 
-	ec->renderer->destroy(ec);
-
 	weston_compositor_shutdown(ec); /* destroys outputs, too */
 
 	XCloseDisplay(compositor->dpy);
diff --git a/src/compositor.c b/src/compositor.c
index ff0f3ab..329ee49 100644
--- a/src/compositor.c
+++ b/src/compositor.c
@@ -3734,6 +3734,9 @@
 	wl_list_for_each_safe(output, next, &ec->output_list, link)
 		output->destroy(output);
 
+	if (ec->renderer)
+		ec->renderer->destroy(ec);
+
 	weston_binding_list_destroy_all(&ec->key_binding_list);
 	weston_binding_list_destroy_all(&ec->button_binding_list);
 	weston_binding_list_destroy_all(&ec->touch_binding_list);