Fix host_arch detection for AIX and one new warning as error

build/detect_v8_host_arch.py

 #!/usr/bin/env python
 # Copyright 2014 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 #       copyright notice, this list of conditions and the following
@@ skipping 23 matching lines @@
 
 
 def main():
   print DoMain([])
   return 0
 
 def DoMain(_):
   """Hook to be called from gyp without starting a separate python
   interpreter."""
   host_arch = platform.machine()
+  host_system = platform.system();
 
   # 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'
   elif host_arch == 'aarch64':
     host_arch = 'arm64'
   elif host_arch == 'mips64':
     host_arch = 'mips64el'
   elif host_arch.startswith('mips'):
     host_arch = 'mipsel'
 
+  # Under AIX the value returned by platform.machine is not
+  # the best indicator of the host architecture
+  # AIX 6.1 which is the lowest level supported only provides
+  # a 64 bit kernel
+  if host_system == 'AIX':
+    host_arch = 'ppc64'
+
   # 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'
 
   return host_arch
 
 if __name__ == '__main__':
   sys.exit(main())