Use signal-block around fork() to avoid we block it.

runtime/bin/process_macos.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "platform/globals.h"
 #if defined(TARGET_OS_MACOS)
 
 #include "bin/process.h"
 
 #include <errno.h>  // NOLINT
@@ skipping 132 matching lines @@
 
     if (!running_) {
       return;
     }
 
     // Set terminate_done_ to false, so we can use it as a guard for our
     // monitor.
     running_ = false;
 
     // Fork to wake up waitpid.
-    if (TEMP_FAILURE_RETRY(fork()) == 0) {
+    if (TEMP_FAILURE_RETRY_BLOCK_SIGNALS(fork()) == 0) {
       exit(0);
     }
 
     monitor_->Notify();
 
     while (!terminate_done_) {
       monitor_->Wait(dart::Monitor::kNoTimeout);
     }
   }
 
@@ skipping 178 matching lines @@
 
   char** program_environment = NULL;
   if (environment != NULL) {
     program_environment = new char*[environment_length + 1];
     for (int i = 0; i < environment_length; i++) {
       program_environment[i] = environment[i];
     }
     program_environment[environment_length] = NULL;
   }
 
-  pid = TEMP_FAILURE_RETRY(fork());
+  pid = TEMP_FAILURE_RETRY_BLOCK_SIGNALS(fork());
   if (pid < 0) {
     SetChildOsErrorMessage(os_error_message);
     delete[] program_arguments;
     VOID_TEMP_FAILURE_RETRY(close(read_in[0]));
     VOID_TEMP_FAILURE_RETRY(close(read_in[1]));
     VOID_TEMP_FAILURE_RETRY(close(read_err[0]));
     VOID_TEMP_FAILURE_RETRY(close(read_err[1]));
     VOID_TEMP_FAILURE_RETRY(close(write_out[0]));
     VOID_TEMP_FAILURE_RETRY(close(write_out[1]));
     VOID_TEMP_FAILURE_RETRY(close(exec_control[0]));
@@ skipping 425 matching lines @@
     bzero(&act, sizeof(act));
     act.sa_handler = SIG_DFL;
     VOID_TEMP_FAILURE_RETRY_BLOCK_SIGNALS(sigaction(signal, &act, NULL));
   }
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_MACOS)