diff --git a/simgear/io/DNSClient.cxx b/simgear/io/DNSClient.cxx
index 07547bc3..080d84ec 100644
--- a/simgear/io/DNSClient.cxx
+++ b/simgear/io/DNSClient.cxx
@@ -22,9 +22,13 @@
 //
 
 #include <simgear_config.h>
+
+#include <algorithm>
+
 #include "DNSClient.hxx"
 #include <udns.h>
-#include <time.h>
+#include <ctime>
+
 #include <simgear/debug/logstream.hxx>
 
 namespace simgear {
diff --git a/simgear/props/props_test.cxx b/simgear/props/props_test.cxx
index 2f61bfbb..14211040 100644
--- a/simgear/props/props_test.cxx
+++ b/simgear/props/props_test.cxx
@@ -9,6 +9,7 @@
 
 #include <simgear/compiler.h>
 
+#include <algorithm>
 #include <memory>               // std::unique_ptr
 #include <iostream>
 #include <map>