GN: aix port along with linux_s390x, linux_ppc64 and linux_ppc64le support.

base/sys_info_posix.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/sys_info.h"
 
 #include <errno.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <string.h>
@@ skipping 201 matching lines @@
   struct utsname info;
   if (uname(&info) < 0) {
     NOTREACHED();
     return std::string();
   }
   std::string arch(info.machine);
   if (arch == "i386" || arch == "i486" || arch == "i586" || arch == "i686") {
     arch = "x86";
   } else if (arch == "amd64") {
     arch = "x86_64";
+  } else if (std::string(info.sysname) == "AIX") {
+    arch = "ppc64";
   }
   return arch;
 }
 
 // static
 size_t SysInfo::VMAllocationGranularity() {
   return getpagesize();
 }
 
 }  // namespace base