diff --git src/notify.hxx src/notify.hxx
index 3e62a01..1213fb6 100644
--- src/notify.hxx
+++ src/notify.hxx
@@ -28,7 +28,7 @@ struct notify {
 	Cond cond;
 	bool pending;
 
-#if !defined(WIN32) && !defined(__NetBSD__) && !defined(__BIONIC__)
+#if defined(__GLIBC__)
 	constexpr
 #endif
 	notify():pending(false) {}
