+@ support ancient toolchains (gcc 2.95.3 has upto 225)
+#ifndef __NR_futex
+#define __NR_futex (__NR_SYSCALL_BASE+240)
+#endif
+#ifndef __NR_exit_group
+#define __NR_exit_group (__NR_SYSCALL_BASE+248)
+#endif
+#ifndef __NR_clock_gettime
+#define __NR_clock_gettime (__NR_SYSCALL_BASE+263)
+#endif