sysroot installer: Don't error out for unknown target archs

build/linux/sysroot_scripts/install-sysroot.py

 #!/usr/bin/env python
 # Copyright (c) 2013 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.
 
 """Install Debian Wheezy sysroots for building chromium.
 """
 
 # The sysroot is needed to ensure that binaries will run on Debian Wheezy,
 # the oldest supported linux distribution.  This script can be run manually but
@@ skipping 89 matching lines @@
   if target_arch == 'x64':
     return 'amd64'
   elif target_arch == 'ia32':
     return 'i386'
   elif target_arch == 'arm':
     return 'arm'
   elif target_arch == 'arm64':
     return 'arm64'
   elif target_arch == 'mipsel':
     return 'mips'
-  elif target_arch:
-    raise Error('Unrecognized target_arch: %s' % target_arch)
 
   return None
 
 
 def InstallDefaultSysroots():
   """Install the default set of sysroot images.
 
   This includes at least the sysroot for host architecture, and the 32-bit
   sysroot for building the v8 snapshot image.  It can also include the cross
   compile sysroot for ARM/MIPS if cross compiling environment can be detected.
@@ skipping 93 matching lines @@
   with open(stamp, 'w') as s:
     s.write(url)
 
 
 if __name__ == '__main__':
   try:
     sys.exit(main(sys.argv[1:]))
   except Error as e:
     sys.stderr.write(str(e) + '\n')
     sys.exit(1)