diff --git a/libxo/xo_syslog.c b/libxo/xo_syslog.c
index 62da1811..0e03916e 100644
--- a/libxo/xo_syslog.c
+++ b/libxo/xo_syslog.c
@@ -58,13 +58,16 @@
 #include <stdarg.h>
 #include <sys/time.h>
 #include <sys/types.h>
-#include <sys/sysctl.h>
 
 #include "xo_config.h"
 #include "xo.h"
 #include "xo_encoder.h"		/* For xo_realloc */
 #include "xo_buf.h"
 
+#ifdef HAVE_SYS_SYSCTL_H
+#include <sys/sysctl.h>
+#endif
+
 /*
  * SYSLOG (RFC 5424) requires an enterprise identifier.  This turns
  * out to be a fickle little issue.  For a single-vendor box, the