signal: Define __ARCH_HAS_SA_RESTORER so we know whether to clear sa_restorer

flush_signal_handlers() needs to know whether sigaction::sa_restorer
is defined, not whether SA_RESTORER is defined.  Define the
__ARCH_HAS_SA_RESTORER macro to indicate this.

Vaguely based on upstream commit 574c4866 'consolidate kernel-side
struct sigaction declarations'.
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: Al Viro <viro@zeniv.linux.org.uk>

arch/arm/include/asm/signal.h

@@ -127,6 +127,7 @@ struct sigaction {
 	__sigrestore_t sa_restorer;
 	sigset_t sa_mask;		/* mask last for extensibility */
 };
+#define __ARCH_HAS_SA_RESTORER
 
 struct k_sigaction {
 	struct sigaction sa;

arch/avr32/include/asm/signal.h

@@ -128,6 +128,7 @@ struct sigaction {
 	__sigrestore_t sa_restorer;
 	sigset_t sa_mask;		/* mask last for extensibility */
 };
+#define __ARCH_HAS_SA_RESTORER
 
 struct k_sigaction {
 	struct sigaction sa;

arch/cris/include/asm/signal.h

@@ -122,6 +122,7 @@ struct sigaction {
 	void (*sa_restorer)(void);
 	sigset_t sa_mask;		/* mask last for extensibility */
 };
+#define __ARCH_HAS_SA_RESTORER
 
 struct k_sigaction {
 	struct sigaction sa;

arch/h8300/include/asm/signal.h

@@ -121,6 +121,7 @@ struct sigaction {
 	void (*sa_restorer)(void);
 	sigset_t sa_mask;		/* mask last for extensibility */
 };
+#define __ARCH_HAS_SA_RESTORER
 
 struct k_sigaction {
 	struct sigaction sa;

arch/m32r/include/asm/signal.h

@@ -123,6 +123,7 @@ struct sigaction {
 	__sigrestore_t sa_restorer;
 	sigset_t sa_mask;		/* mask last for extensibility */
 };
+#define __ARCH_HAS_SA_RESTORER
 
 struct k_sigaction {
 	struct sigaction sa;

arch/m68k/include/asm/signal.h

@@ -119,6 +119,7 @@ struct sigaction {
 	__sigrestore_t sa_restorer;
 	sigset_t sa_mask;		/* mask last for extensibility */
 };
+#define __ARCH_HAS_SA_RESTORER
 
 struct k_sigaction {
 	struct sigaction sa;

arch/mn10300/include/asm/signal.h

@@ -131,6 +131,7 @@ struct sigaction {
 	__sigrestore_t sa_restorer;
 	sigset_t sa_mask;		/* mask last for extensibility */
 };
+#define __ARCH_HAS_SA_RESTORER
 
 struct k_sigaction {
 	struct sigaction sa;

arch/powerpc/include/asm/signal.h

@@ -109,6 +109,7 @@ struct sigaction {
 	__sigrestore_t sa_restorer;
 	sigset_t sa_mask;		/* mask last for extensibility */
 };
+#define __ARCH_HAS_SA_RESTORER
 
 struct k_sigaction {
 	struct sigaction sa;

arch/s390/include/asm/signal.h

@@ -131,6 +131,7 @@ struct sigaction {
         void (*sa_restorer)(void);
         sigset_t sa_mask;               /* mask last for extensibility */
 };
+#define __ARCH_HAS_SA_RESTORER
 
 struct k_sigaction {
         struct sigaction sa;

arch/sparc/include/asm/signal.h

@@ -191,6 +191,7 @@ struct __old_sigaction {
 	unsigned long		sa_flags;
 	void			(*sa_restorer)(void);  /* not used by Linux/SPARC yet */
 };
+#define __ARCH_HAS_SA_RESTORER
 
 typedef struct sigaltstack {
 	void			__user *ss_sp;

arch/x86/include/asm/signal.h

@@ -125,6 +125,8 @@ typedef unsigned long sigset_t;
 extern void do_notify_resume(struct pt_regs *, void *, __u32);
 # endif /* __KERNEL__ */
 
+#define __ARCH_HAS_SA_RESTORER
+
 #ifdef __i386__
 # ifdef __KERNEL__
 struct old_sigaction {

arch/xtensa/include/asm/signal.h

@@ -133,6 +133,7 @@ struct sigaction {
 	void (*sa_restorer)(void);
 	sigset_t sa_mask;		/* mask last for extensibility */
 };
+#define __ARCH_HAS_SA_RESTORER
 
 struct k_sigaction {
 	struct sigaction sa;

include/asm-generic/signal.h

@@ -99,6 +99,10 @@ typedef unsigned long old_sigset_t;
 
 #include <asm-generic/signal-defs.h>
 
+#ifdef SA_RESTORER
+#define __ARCH_HAS_SA_RESTORER
+#endif
+
 struct sigaction {
 	__sighandler_t sa_handler;
 	unsigned long sa_flags;