#define cmm_wmb() __asm__ __volatile__ ("wmb":::"memory")
#define cmm_read_barrier_depends() __asm__ __volatile__ ("mb":::"memory")
+/*
+ * On Linux, define the membarrier system call number if not yet available in
+ * the system headers.
+ */
+#if (defined(__linux__) && !defined(__NR_membarrier))
+#define __NR_membarrier 517
+#endif
+
#ifdef __cplusplus
}
#endif