consolidate kernel-side struct sigaction declarations

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/arch/cris/include/asm/signal.h b/arch/cris/include/asm/signal.h
index b0cd904..b3650ab 100644
--- a/arch/cris/include/asm/signal.h
+++ b/arch/cris/include/asm/signal.h
@@ -23,12 +23,7 @@
 	void (*sa_restorer)(void);
 };
 
-struct sigaction {
-	__sighandler_t sa_handler;
-	unsigned long sa_flags;
-	void (*sa_restorer)(void);
-	sigset_t sa_mask;		/* mask last for extensibility */
-};
+#define __ARCH_HAS_SA_RESTORER
 
 #include <asm/sigcontext.h>