Missing #include, as the split_member.hpp include is not
part of the nvp.hpp interface, and hence cannot be relied
upon to be included transitively.

Confirmed on
https://github.com/boostorg/serialization/commit/c32a663c9963385430abc563f9c85f94d8da43a9#r36528430

Bug: https://bugs.gentoo.org/703294

--- a/boost/bimap/detail/map_view_iterator.hpp
+++ b/boost/bimap/detail/map_view_iterator.hpp
@@ -22,6 +22,7 @@
 
 #ifndef BOOST_BIMAP_DISABLE_SERIALIZATION
   #include <boost/serialization/nvp.hpp>
+  #include <boost/serialization/split_member.hpp>
 #endif // BOOST_BIMAP_DISABLE_SERIALIZATION
 
 #include <boost/iterator/detail/enable_if.hpp>
--- a/boost/bimap/detail/set_view_iterator.hpp
+++ b/boost/bimap/detail/set_view_iterator.hpp
@@ -22,6 +22,7 @@
 
 #ifndef BOOST_BIMAP_DISABLE_SERIALIZATION 
   #include <boost/serialization/nvp.hpp>
+  #include <boost/serialization/split_member.hpp>
 #endif // BOOST_BIMAP_DISABLE_SERIALIZATION
 
 #include <boost/iterator/detail/enable_if.hpp>