--- ceph-15.1.0/src/common/bit_str.h.orig	2020-02-03 09:47:20.047149798 -0500

+++ ceph-15.1.0/src/common/bit_str.h	2020-02-03 09:47:50.213149798 -0500

@@ -17,6 +17,7 @@

 #include <cstdint>

 #include <iosfwd>

 #include <functional>

+#include <ostream>

 namespace ceph {

   class Formatter;