diff --git a/libcxx/src/atomic.cpp b/libcxx/src/atomic.cpp
--- a/libcxx/src/atomic.cpp
+++ b/libcxx/src/atomic.cpp
@@ -14,6 +14,9 @@
 #include <functional>
 
 #ifdef __linux__
+#if !defined(SYS_futex) && defined(SYS_futex_time64)
+# define SYS_futex SYS_futex_time64
+#endif
 
 #include <unistd.h>
 #include <linux/futex.h>