[NaCl SDK] Remove newlib toolchain from the SDK

native_client_sdk/src/examples/tutorial/multi_platform/example.dsc

 {
-  'TOOLS': ['newlib', 'glibc'],
+  'TOOLS': ['clang-newlib', 'glibc'],
   'TARGETS': [
     {
       'NAME': 'multi_platform',
       'TYPE': 'main',
       'SOURCES': ['multi_platform.cc'],
       'LIBS': ['ppapi_cpp', 'ppapi', 'pthread'],
     }
   ],
   'DATA': [
     'example.js',
     'README',
   ],
   'DEST': 'examples/tutorial',
   'NAME': 'multi_platform',
   'TITLE': 'Multi-platform App',
   'GROUP': 'Tutorial',
   'MULTI_PLATFORM': True,
 }