diff --git a/include/maxscale/cdefs.h b/include/maxscale/cdefs.h
index 3b24b55c9..4f163ee1e 100644
--- a/include/maxscale/cdefs.h
+++ b/include/maxscale/cdefs.h
@@ -33,6 +33,9 @@
 # define MXS_END_DECLS
 #endif
 
+#define _XOPEN_SOURCE 700
+#define OPENSSL_THREAD_DEFINES
+
 /**
  * Define intended for use with strerror.
  *
diff --git a/server/core/gateway.c b/server/core/gateway.c
index 67eb2e9a9..309565bcb 100644
--- a/server/core/gateway.c
+++ b/server/core/gateway.c
@@ -34,8 +34,8 @@
  * 19/01/16     Markus Makela           Set cwd to log directory
  * @endverbatim
  */
-#define _XOPEN_SOURCE 700
-#define OPENSSL_THREAD_DEFINES
+
+#include <maxscale/cdefs.h>
 #include <my_config.h>
 
 #include <openssl/opensslconf.h>