diff --git a/include/xorg-server.h.meson.in b/include/xorg-server.h.meson.in
index 772b7af3c..6f7a1af29 100644
--- a/include/xorg-server.h.meson.in
+++ b/include/xorg-server.h.meson.in
@@ -214,4 +214,7 @@
 #define XORG_API_DIX_SCREEN_HOOK_CLOSE 1
 #define XORG_API_DIX_SCREEN_HOOK_PIXMAP_DESTROY 1
 
+/* needed for os.h to prevent redefinition of timingsafe_memcmp in drivers */
+#mesondefine HAVE_TIMINGSAFE_MEMCMP
+
 #endif /* _XORG_SERVER_H_ */