Add x86_64 to the bionic headers.

Manual changes:

  cpp.py: cope with macros that refer to other macros.

  defaults.py: x86 no longer always implies __i386__; use __i386__ to replace
  the kernel CONFIG_X86_32 flag.

  asm/page.h: the upstream page.h isn't a uapi header and no longer includes
  the stuff we were using it for. Let's just have our own static file, since
  it's the same for all our architectures (both 32- and 64-bit).

  sys/select.h: we used to use the various FD_SET-related macros from the
  kernel header files, but they've gone. Adjust by adding trivial equivalent
  definitions.

Automated changes:

  libc/kernel/arch-x86, libc/kernel/common: regenerated from
  external/kernel-headers.

Change-Id: I84fc0ed52dc742e043b4ae300fd3b58ee99b7fcd
diff --git a/libc/kernel/arch-x86/asm/signal.h b/libc/kernel/arch-x86/asm/signal.h
index 1c8f2f6..a15028c 100644
--- a/libc/kernel/arch-x86/asm/signal.h
+++ b/libc/kernel/arch-x86/asm/signal.h
@@ -93,20 +93,35 @@
 /* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #include <asm-generic/signal.h>
 #ifndef __ASSEMBLY__
+#ifdef __i386__
 struct sigaction {
- union {
 /* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
+ union {
  __sighandler_t _sa_handler;
  void (*_sa_sigaction)(int, struct siginfo *, void *);
  } _u;
- sigset_t sa_mask;
 /* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
+ sigset_t sa_mask;
  unsigned long sa_flags;
  void (*sa_restorer)(void);
 };
-#define sa_handler _u._sa_handler
 /* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
+#define sa_handler _u._sa_handler
 #define sa_sigaction _u._sa_sigaction
+#else
+struct sigaction {
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
+ __sighandler_t sa_handler;
+ unsigned long sa_flags;
+ __sigrestore_t sa_restorer;
+ sigset_t sa_mask;
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
+};
+struct k_sigaction {
+ struct sigaction sa;
+};
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
+#endif
 typedef struct sigaltstack {
  void __user *ss_sp;
  int ss_flags;