[common] use libc++ provided jthread instead of in-house one (which deadlocks on FBSD 14)

Signed-off-by: lizzie <lizzie@eden-emu.dev>

src/common/thread.h

@@ -80,7 +80,7 @@ public:
             condvar.notify_all();
             return true;
         } else {
-            CondvarWait(condvar, lk, token,
+            condvar.wait(lk, token,
                         [this, current_generation] { return current_generation != generation; });
             return !token.stop_requested();
         }