kernel+launch: Always send SIGCHLD when a child exits

POSIX says so. I thought it was only when the parent wasn't actively waiting, to signal it, but it turns out it's always sent.

gui/apps/taskbar.cpp

@@ -19,11 +19,6 @@ static constexpr ui::Color TASKBAR_COLOR = ui::Color::from_rgb(83, 83, 83);
 
 static OwnedPtr<os::IPC::Client> launcher_client;
 
-void sigchld_handler(int)
-{
-    wait(nullptr);
-}
-
 void sigquit_handler(int)
 {
     // Reload the taskbar by exec-ing the executable, resetting everything.
@@ -118,7 +113,6 @@ Result<int> luna_main(int, char**)
     ui::App app;
     TRY(app.init("/tmp/wsys.sock"));
 
-    TRY(os::EventLoop::the().register_signal_handler(SIGCHLD, sigchld_handler));
     TRY(os::EventLoop::the().register_signal_handler(SIGQUIT, sigquit_handler));
 
     launcher_client = TRY(os::IPC::Client::connect("/tmp/launch.sock", false));

gui/launch.cpp

@@ -48,7 +48,7 @@ void handle_ipc_message(os::IPC::ClientConnection& client, u8 id, void*)
 
 void sigchld_handler(int)
 {
-    os::Process::wait(os::Process::ANY_CHILD, nullptr);
+    os::Process::wait(os::Process::ANY_CHILD, nullptr, WNOHANG);
 }
 
 Result<int> luna_main(int argc, char** argv)

kernel/src/thread/Thread.cpp

@@ -147,11 +147,8 @@ Result<SharedPtr<VFS::Inode>> Thread::resolve_atfile(int dirfd, const String& pa
                 parent->wake_up();
             }
         }
-        else
-        {
-            while (parent->pending_signals.get(SIGCHLD - 1)) kernel_yield();
-            parent->send_signal(SIGCHLD);
-        }
+        while (parent->pending_signals.get(SIGCHLD - 1)) kernel_yield();
+        parent->send_signal(SIGCHLD);
     }
 
     state = ThreadState::Exited;