output: let wlr_output_layout manage wl_output globals

Creating a wl_output global ourselves causes the wlroots xdg-output
implementation to hit an assertion failure. It's not worth fighting with
these APIs.

 river/Output.zig        | 12 +++++++-----
 river/OutputManager.zig |  1 +
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/river/Output.zig b/river/Output.zig
index eb222db..a05b7ff 100644
--- a/river/Output.zig
+++ b/river/Output.zig
@@ -139,6 +139,7 @@ scheduled: State,
 /// State sent to the wm in the latest manage sequence.
 sent: State,
 link_sent: wl.list.Link,
+sent_wl_output: bool = false,
 /// State applied to the wlr_output and rendered.
 current: State,
 
@@ -239,11 +240,12 @@ pub fn manageStart(output: *Output) void {
                 const pending = &output.scheduled;
                 const sent = &output.sent;
 
-                if (new) {
-                    // Ensure that the wl_output global has been created,
-                    // this is a noop if it already has been.
-                    wlr_output.createGlobal(server.wl_server);
-                    output_v1.sendWlOutput(wlr_output.global.?.getName(output_v1.getClient()));
+                if (!output.sent_wl_output) {
+                    // wl_output globals are created/destroyed by the wlroots output layout.
+                    if (wlr_output.global) |global| {
+                        output_v1.sendWlOutput(global.getName(output_v1.getClient()));
+                        output.sent_wl_output = true;
+                    }
                 }
 
                 const pending_width, const pending_height = pending.dimensions();
diff --git a/river/OutputManager.zig b/river/OutputManager.zig
index 03175cb..1426260 100644
--- a/river/OutputManager.zig
+++ b/river/OutputManager.zig
@@ -259,6 +259,7 @@ pub fn commitOutputState(om: *OutputManager) void {
                 },
                 .disabled_hard, .destroying => {
                     om.output_layout.remove(wlr_output);
+                    output.sent_wl_output = false;
                 },
             }
         }