commit 5198966c8d5fec89116d025c74934ac03ea511fa
Author: Dimitri van Heesch <doxygen@gmail.com>
Date:   Fri May 6 09:55:16 2022 +0200

    issue #9312: Build: cache.h:53:14: error: 'exchange' is not a member of 'std'

diff --git a/src/cache.h b/src/cache.h
index 0ff3092e..e218eb27 100644
--- a/src/cache.h
+++ b/src/cache.h
@@ -19,6 +19,7 @@
 #include <list>
 #include <unordered_map>
 #include <mutex>
+#include <utility>
 #include <ctype.h>
 
 /*! Fixed size cache for value type V using keys of type K.