diff --git a/src/helper/slbt_realpath.c b/src/helper/slbt_realpath.c
index dc1b13b..6d74a82 100644
--- a/src/helper/slbt_realpath.c
+++ b/src/helper/slbt_realpath.c
@@ -14,7 +14,7 @@
 #include "slibtool_driver_impl.h"
 #include "slibtool_readlink_impl.h"
 
-#ifdef __unix__
+#ifdef HAVE_SYS_SYSCALL_H
 #include <sys/syscall.h>
 #endif