Build fix for ia64: Declare __clone2 in lxc/namespace.h

src/lxc/namespace.h

@@ -49,7 +49,11 @@
 #ifndef CLONE_NEWNET
 #  define CLONE_NEWNET            0x40000000
 #endif
-#ifdef IS_BIONIC
+
+#if defined(__ia64__)
+int __clone2(int (*__fn) (void *__arg), void *__child_stack_base,
+             size_t __child_stack_size, int __flags, void *__arg, ...);
+#elif defined(IS_BIONIC)
 int clone(int (*fn)(void *), void *child_stack,
 	int flags, void *arg);
 #else