support archs with no mlock syscall, only mlock2

src/mman/mlock.c

@@ -3,5 +3,9 @@
 
 int mlock(const void *addr, size_t len)
 {
+#ifdef SYS_mlock
 	return syscall(SYS_mlock, addr, len);
+#else
+	return syscall(SYS_mlock2, addr, len, 0);
+#endif
 }