diff --git a/src/notify.hxx b/src/notify.hxx
index a077f9d02..b1bc594be 100644
--- a/src/notify.hxx
+++ b/src/notify.hxx
@@ -28,8 +28,7 @@ struct notify {
 	Cond cond;
 	bool pending;
 
-#if !defined(WIN32) && !defined(__NetBSD__) && !defined(__BIONIC__) && \
-	!defined(__HAIKU__)
+#ifdef __GLIBC__
 	constexpr
 #endif
 	notify():pending(false) {}