rec: only notice if boost flat_set are not available

diff --git a/pdns/recursordist/configure.ac b/pdns/recursordist/configure.ac
index 5fd62492714c9eb08d53cd200971b73fa663a421..08ed1f51c3c04812950a18a4aa991336f8aefa95 100644 (file)
--- a/pdns/recursordist/configure.ac
+++ b/pdns/recursordist/configure.ac
@@ -92,7 +92,7 @@ AS_IF([test "x$PROTOBUF_LIBS" != "x" -a x"$PROTOC" != "x"],
 BOOST_REQUIRE([$boost_required_version])
 
 # Check against flat_set header that requires boost >= 1.48
-BOOST_FIND_HEADER([boost/container/flat_set.hpp])
+BOOST_FIND_HEADER([boost/container/flat_set.hpp], [AC_MSG_NOTICE([boost::container::flat_set not available, will fallback to std::set])])
 
 PDNS_SELECT_CONTEXT_IMPL