Revert and fix more of the mac change.

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 <crt_externs.h>  // NOLINT
@@ skipping 434 matching lines @@
     if (TEMP_FAILURE_RETRY(dup2(read_err_[1], STDERR_FILENO)) == -1) {
       ReportChildError();
     }
 
     if (working_directory_ != NULL &&
         TEMP_FAILURE_RETRY(chdir(working_directory_)) == -1) {
       ReportChildError();
     }
 
     if (program_environment_ != NULL) {
-      environ = program_environment_;
+      // On MacOS you have to do a bit of magic to get to the
+      // environment strings.
+      char*** environ = _NSGetEnviron();
+      *environ = program_environment_;
     }
 
     VOID_TEMP_FAILURE_RETRY(
         execvp(path_, const_cast<char* const*>(program_arguments_)));
 
     ReportChildError();
   }
 
 
   void ExecDetachedProcess() {
@@ skipping 180 matching lines @@
     // If CleanupAndReturnError is called without an actual errno make
     // sure to return an error anyway.
     if (actual_errno == 0) actual_errno = EPERM;
     SetChildOsErrorMessage();
     CloseAllPipes();
     return actual_errno;
   }
 
 
   void SetChildOsErrorMessage() {
-    const int kBufferSize = 1024;
-    char error_message[kBufferSize];
-    strerror_r(errno, error_message, kBufferSize);
-    *os_error_message_ = strdup(error_message);
+    SetOSErrorMessage(errno);
   }
 
 
   void ReportChildError() {
     // In the case of failure in the child process write the errno to the exec
     // control pipe and exit.
     int child_errno = errno;
     FDUtils::WriteToBlocking(
         exec_control_[1], &child_errno, sizeof(child_errno));
     _exit(1);
   }
 
 
   void ReportPid(int pid) {
     // In the case of starting a detached process the actual pid of that process
     // is communicated using the exec control pipe.
     int bytes_written =
         FDUtils::WriteToBlocking(exec_control_[1], &pid, sizeof(pid));
     ASSERT(bytes_written == sizeof(int));
     USE(bytes_written);
   }
 
 
   void SetOSErrorMessage(int child_errno) {
-    const int kMaxMessageSize = 256;
-    char* message = static_cast<char*>(calloc(kMaxMessageSize, 0));
-    strerror_r(child_errno, message, kMaxMessageSize - 1);
-    *os_error_message_ = message;
+    const int kBufferSize = 1024;
+    char error_message[kBufferSize];
+    strerror_r(child_errno, error_message, kBufferSize);
+    *os_error_message_ = strdup(error_message);
   }
 
 
   void ClosePipe(int* fds) {
     for (int i = 0; i < 2; i++) {
       if (fds[i] != -1) {
         VOID_TEMP_FAILURE_RETRY(close(fds[i]));
         fds[i] = -1;
       }
     }
@@ skipping 344 matching lines @@
     bzero(&act, sizeof(act));
     act.sa_handler = SIG_DFL;
     VOID_NO_RETRY_EXPECTED(sigaction(signal, &act, NULL));
   }
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_MACOS)