Make gyp autodetection of host_arch work for 64-bit kernel and 32-bit userland

build/linux/detect_host_arch.py

+#!/usr/bin/env python
+# Copyright 2014 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.
+
+"""Outputs host CPU architecture in format recognized by gyp."""
+
+import platform
+import re
+import sys
+
+
+def main():
+  host_arch = platform.machine()
+
+  # Convert machine type to format recognized by gyp.
+  if re.match(r'i.86', host_arch) or host_arch == 'i86pc':
+    host_arch = 'ia32'
+  elif host_arch in ['x86_64', 'amd64']:
+    host_arch = 'x64'
+  elif host_arch.startswith('arm'):
+    host_arch = 'arm'
+
+  # platform.machine is based on running kernel. It's possible to use 64-bit
+  # kernel with 32-bit userland, e.g. to give linker slightly more memory.
+  # Distinguish between different userland bitness by querying
+  # the python binary.
+  if host_arch == 'x64' and platform.architecture()[0] == '32bit':
+    host_arch = 'ia32'
+
+  print host_arch
+  return 0
+
+if __name__ == '__main__':
+  sys.exit(main())