diff --git a/source/texk/web2c/luatexdir/luaffi/ffi.h b/source/texk/web2c/luatexdir/luaffi/ffi.h
index 08f280940f20ccbdc465cdf2dea6b7b520e669e5..75fe9c8a87a5b9b7941d9246c7aa5a593178e3ce 100644
--- a/source/texk/web2c/luatexdir/luaffi/ffi.h
+++ b/source/texk/web2c/luatexdir/luaffi/ffi.h
@@ -42,7 +42,7 @@ extern "C" {
 #include <sys/mman.h>
 #endif
 
-#ifdef _WIN32 || __FreeBSD__ || __NetBSD__ || __bsdi__ || __DragonFly__
+#if ( defined( _WIN32) || defined(__FreeBSD__) || defined(__NetBSD__) || defined(__bsdi__) || defined(__DragonFly__))
 /* We should include something equivalent to */
 /* complex.h                                 */
 #else