y2038: signal: Add sys_rt_sigtimedwait_time32

Once sys_rt_sigtimedwait() gets changed to a 64-bit time_t, we have
to provide compatibility support for existing binaries.

An earlier version of this patch reused the compat_sys_rt_sigtimedwait
entry point to avoid code duplication, but this newer approach
duplicates the existing native entry point instead, which seems
a bit cleaner.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 03cda67..251979d 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -649,6 +649,10 @@ asmlinkage long sys_rt_sigtimedwait(const sigset_t __user *uthese,
 				siginfo_t __user *uinfo,
 				const struct __kernel_timespec __user *uts,
 				size_t sigsetsize);
+asmlinkage long sys_rt_sigtimedwait_time32(const sigset_t __user *uthese,
+				siginfo_t __user *uinfo,
+				const struct old_timespec32 __user *uts,
+				size_t sigsetsize);
 asmlinkage long sys_rt_sigqueueinfo(pid_t pid, int sig, siginfo_t __user *uinfo);
 
 /* kernel/sys.c */