https://bugs.gentoo.org/786855

From 4ec818f0d337a54ff3d4ff587bbd6f5f05363700 Mon Sep 17 00:00:00 2001
From: Sam James <sam@gentoo.org>
Date: Wed, 4 Aug 2021 23:14:21 +0100
Subject: [PATCH] Add missing include

---
 lib/include/srslte/adt/observer.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lib/include/srslte/adt/observer.h b/lib/include/srslte/adt/observer.h
index 38a881d..9ad33a0 100644
--- a/lib/include/srslte/adt/observer.h
+++ b/lib/include/srslte/adt/observer.h
@@ -26,6 +26,7 @@
 #include <functional>
 #include <limits>
 #include <vector>
+#include <cstddef>
 
 namespace srslte {
 
-- 
2.32.0