Move signal_blocker to platform and use it by default in TEMP_FAILURE_RETRY.

runtime/bin/eventhandler_linux.h

Index: runtime/bin/eventhandler_linux.h
diff --git a/runtime/bin/eventhandler_linux.h b/runtime/bin/eventhandler_linux.h
index 9341cd11f3ec30d9c7c5b13b1b4b60c33d764499..54f02509531446572bf84b1e489df896cc95b19c 100644
--- a/runtime/bin/eventhandler_linux.h
+++ b/runtime/bin/eventhandler_linux.h
@@ -9,11 +9,13 @@
 #error Do not include eventhandler_linux.h directly; use eventhandler.h instead.
 #endif
 
-#include <unistd.h>
+#include <errno.h>
 #include <sys/epoll.h>
 #include <sys/socket.h>
+#include <unistd.h>
 
 #include "platform/hashmap.h"
+#include "platform/signal_blocker.h"
 
 
 namespace dart {
@@ -38,7 +40,7 @@ class SocketData {
   void Close() {
     port_ = 0;
     mask_ = 0;
-    close(fd_);
+    VOID_TEMP_FAILURE_RETRY(close(fd_));
     fd_ = -1;
   }