Reland "Non-SFI mode: Add Linux asynchronous signal support"

src/nonsfi/linux/linux_syscall_defines.h

 /*
  * Copyright 2014 The Native Client Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef NATIVE_CLIENT_SRC_NONSFI_LINUX_LINUX_SYSCALL_DEFINES_H_
 #define NATIVE_CLIENT_SRC_NONSFI_LINUX_LINUX_SYSCALL_DEFINES_H_ 1
 
 #define FUTEX_WAIT_PRIVATE 128
 #define FUTEX_WAKE_PRIVATE 129
 
 #define LINUX_TCGETS 0x5401
 
 #define LINUX_SIG_UNBLOCK 1
 
 #define LINUX_SA_SIGINFO 0x00000004
+#define LINUX_SA_ONSTACK 0x08000000
+#define LINUX_SA_NODEFER 0x40000000
 #define LINUX_SA_RESTART 0x10000000
-#define LINUX_SA_ONSTACK 0x08000000
 
 /* From linux/arch/{arch}/include/uapi/asm/signal.h */
 #if defined(__mips__)
 /*
  * We at least know the numbers are different on MIPS. This part would
  * be guarded by #if defined(__i386__) || defined(__arm__), however
  * this file is included by code which does not have --target set.
  */
 #error "Unsupported architecture"
 #endif
@@ skipping 10 matching lines @@
 #define LINUX_SIGSEGV         11
 #define LINUX_SIGUSR2         12
 #define LINUX_SIGPIPE         13
 #define LINUX_SIGALRM         14
 #define LINUX_SIGTERM         15
 #define LINUX_SIGSTKFLT       16
 #define LINUX_SIGCHLD         17
 #define LINUX_SIGSYS          31
 
 #endif