Factor out toolset definitions in a separate gypi file

samples/samples.gyp

 # Copyright 2012 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
 #       disclaimer in the documentation and/or other materials provided
@@ skipping 11 matching lines @@
 # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 {
   'variables': {
     'v8_code': 1,
   },
-  'includes': ['../build/common.gypi'],
+  'includes': ['../build/toolchain.gypi', '../build/features.gypi'],
   'target_defaults': {
     'type': 'executable',
     'dependencies': [
       '../tools/gyp/v8.gyp:v8',
     ],
     'include_dirs': [
       '../include',
     ],
   },
   'targets': [
@@ skipping 10 matching lines @@
       ],
     },
     {
       'target_name': 'lineprocessor',
       'sources': [
         'lineprocessor.cc',
       ],
     }
   ],
 }