Make it link on x86_64.

Cc: Hien Nguyen <hien@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

 kernel/kprobes.c |    5 +++++
 linux/kprobes.h  |    0 
 2 files changed, 5 insertions(+)

diff -puN include/linux/kprobes.h~kprobes-function-return-probes-fix-2 include/linux/kprobes.h
diff -puN kernel/kprobes.c~kprobes-function-return-probes-fix-2 kernel/kprobes.c
--- 25/kernel/kprobes.c~kprobes-function-return-probes-fix-2	2005-05-10 00:13:15.000000000 -0700
+++ 25-akpm/kernel/kprobes.c	2005-05-10 00:14:18.000000000 -0700
@@ -441,6 +441,11 @@ int register_kretprobe(struct kretprobe 
 	return ret;
 }
 
+void  __attribute__((weak))
+arch_prepare_kretprobe(struct kretprobe *rp, struct pt_regs *regs)
+{
+}
+
 void unregister_kretprobe(struct kretprobe *rp)
 {
 	unsigned long flags;
_