Merge 1447 "Fix call to rt_sigaction"

> Fix call to rt_sigaction
> 
> Despite the fact that many places imply that sigaction and rt_sigaction
> are essentially the same, rt_sigaction's signature is actually
> different-- it takes the size of the kernel's sigset_t as an extra argument.
> 
> BUG=473973
> 

TBR=cjhopman@chromium.org

Review URL: https://breakpad.appspot.com/5784002

git-svn-id: http://google-breakpad.googlecode.com/svn/branches/chrome_42@1448 4c0a9323-5329-0410-9bdc-e9ce6186880e
diff --git a/src/client/linux/handler/exception_handler.cc b/src/client/linux/handler/exception_handler.cc
index 3ddbe66..6a8849d 100644
--- a/src/client/linux/handler/exception_handler.cc
+++ b/src/client/linux/handler/exception_handler.cc
@@ -195,12 +195,12 @@
   // to SIG_DFL is ignored. In that case, an infinite loop is entered as the
   // signal is repeatedly sent to breakpad's signal handler.
   // To work around this, directly call the system's sigaction.
-  struct sigaction sa;
+  struct kernel_sigaction sa;
   memset(&sa, 0, sizeof(sa));
-  sigemptyset(&sa.sa_mask);
-  sa.sa_handler = SIG_DFL;
+  sys_sigemptyset(&sa.sa_mask);
+  sa.sa_handler_ = SIG_DFL;
   sa.sa_flags = SA_RESTART;
-  syscall(__NR_rt_sigaction, sig, &sa, NULL);
+  sys_rt_sigaction(sig, &sa, NULL, sizeof(kernel_sigset_t));
 #else
   signal(sig, SIG_DFL);
 #endif