diff --git a/simgear/ephemeris/ephemeris.cxx b/simgear/ephemeris/ephemeris.cxx
index 80ecd2d9..31ceb01f 100644
--- a/simgear/ephemeris/ephemeris.cxx
+++ b/simgear/ephemeris/ephemeris.cxx
@@ -22,6 +22,9 @@
 //
 // $Id$
 
+#ifdef HAVE_CONFIG_H
+#  include <simgear_config.h>
+#endif
 
 #include <iostream>
 
diff --git a/simgear/ephemeris/stardata.cxx b/simgear/ephemeris/stardata.cxx
index e45b2092..86583ea4 100644
--- a/simgear/ephemeris/stardata.cxx
+++ b/simgear/ephemeris/stardata.cxx
@@ -21,6 +21,9 @@
 //
 // $Id$
 
+#ifdef HAVE_CONFIG_H
+#  include <simgear_config.h>
+#endif
 
 #include <simgear/debug/logstream.hxx>
 #include <simgear/misc/sgstream.hxx>
diff --git a/simgear/io/decode_binobj.cxx b/simgear/io/decode_binobj.cxx
index 70a50f5e..06181c8b 100644
--- a/simgear/io/decode_binobj.cxx
+++ b/simgear/io/decode_binobj.cxx
@@ -1,3 +1,7 @@
+#ifdef HAVE_CONFIG_H
+#  include <simgear_config.h>
+#endif
+
 #include <simgear/compiler.h>
 
 #include <unistd.h>
diff --git a/simgear/io/sg_socket_udp.cxx b/simgear/io/sg_socket_udp.cxx
index b3e4a57e..7c0a0d60 100644
--- a/simgear/io/sg_socket_udp.cxx
+++ b/simgear/io/sg_socket_udp.cxx
@@ -20,6 +20,9 @@
 //
 // $Id$
 
+#ifdef HAVE_CONFIG_H
+#  include <simgear_config.h>
+#endif
 
 #include <simgear/compiler.h>
 
diff --git a/simgear/scene/sky/moon.cxx b/simgear/scene/sky/moon.cxx
index fdf1fc87..cf851e7e 100644
--- a/simgear/scene/sky/moon.cxx
+++ b/simgear/scene/sky/moon.cxx
@@ -24,6 +24,9 @@
 //
 // $Id$
 
+#ifdef HAVE_CONFIG_H
+#  include <simgear_config.h>
+#endif
 
 #include <simgear/compiler.h>