ia64: fix sigaction decoding

Looks like ia64 doesn't have sa_restorer either, yet still defines
SA_RESTORER.  Deploy the same trick that HPPA is using to make the
test pass.

* signal.c (SA_RESTORER): Undefine when IA64 is defined.
(struct new_sigaction) [IA64]: Disable sa_restorer.
diff --git a/signal.c b/signal.c
index 9a7c82f..f6eeed0 100644
--- a/signal.c
+++ b/signal.c
@@ -100,9 +100,9 @@
 # endif
 #endif
 
-/* HPPA defines this in their headers, but doesn't actually have it,
+/* Some arches define this in their headers, but don't actually have it,
    so we have to delete the define.  */
-#ifdef HPPA
+#if defined(HPPA) || defined(IA64)
 # undef SA_RESTORER
 #endif
 
@@ -1134,9 +1134,9 @@
 #else
 	void (*__sa_handler)(int);
 	unsigned long sa_flags;
-# if !defined(ALPHA) && !defined(HPPA)
+# if !defined(ALPHA) && !defined(HPPA) && !defined(IA64)
 	void (*sa_restorer)(void);
-# endif /* !ALPHA && !HPPA */
+# endif /* !ALPHA && !HPPA && !IA64 */
 #endif /* !MIPS */
 	/* Kernel treats sa_mask as an array of longs. */
 	unsigned long sa_mask[NSIG / sizeof(long) ? NSIG / sizeof(long) : 1];