Non-SFI mode: Add Linux asynchronous signal support

src/nonsfi/linux/linux_sys_private.c

 /*
  * Copyright (c) 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.
  */
 
 /*
  * This file defines various POSIX-like functions directly using Linux
  * syscalls.  This is analogous to src/untrusted/nacl/sys_private.c, which
  * defines functions using NaCl syscalls directly.
@@ skipping 592 matching lines @@
 
 int linux_sigprocmask(int how,
                       const linux_sigset_t *set,
                       linux_sigset_t *oset) {
   return errno_value_call(
       linux_syscall4(__NR_rt_sigprocmask, how,
                      (uintptr_t) set, (uintptr_t) oset,
                      sizeof(*set)));
 }
 
+int linux_tgkill(int tgid,

[Mark Seaborn, 2015/06/26 18:31:59]

Nit: args would fit on one line

[Luis Héctor Chávez, 2015/07/06 23:44:59]

Done.

+                 int tid,
+                 int sig) {
+  return errno_value_call(
+      linux_syscall3(__NR_tgkill, tgid, tid, sig));
+}
+
 /*
  * Obtain Linux signal number from portable signal number.
  */
 static int nacl_signum_to_linux_signum(int signum) {
   /* SIGSTKFLT is not defined in newlib, hence no mapping. */
 #define HANDLE_SIGNUM(SIGNUM) case SIGNUM: return LINUX_##SIGNUM;
   switch(signum) {
     HANDLE_SIGNUM(SIGHUP);
     HANDLE_SIGNUM(SIGINT);
     HANDLE_SIGNUM(SIGQUIT);
@@ skipping 228 matching lines @@
   va_list ap;
   va_start(ap, arg);
   void *ptid = va_arg(ap, void *);
   void *tls = va_arg(ap, void *);
   void *ctid = va_arg(ap, void *);
   va_end(ap);
 
   return errno_value_call(linux_clone_wrapper(
       (uintptr_t) fn, (uintptr_t) arg, flags, child_stack, ptid, tls, ctid));
 }