Make build incremental

runtime/bin/bin.gypi

 # Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 {
   'variables': {
     'gen_source_dir': '<(SHARED_INTERMEDIATE_DIR)',
 
     'io_cc_file': '<(gen_source_dir)/io_gen.cc',
     'io_patch_cc_file': '<(gen_source_dir)/io_patch_gen.cc',
     'builtin_in_cc_file': 'builtin_in.cc',
     'builtin_cc_file': '<(gen_source_dir)/builtin_gen.cc',
     'snapshot_in_cc_file': 'snapshot_in.cc',
     'vm_isolate_snapshot_bin_file': '<(gen_source_dir)/vm_isolate_snapshot_gen.bin',
     'isolate_snapshot_bin_file': '<(gen_source_dir)/isolate_snapshot_gen.bin',
+    'gen_snapshot_stamp_file': '<(gen_source_dir)/gen_snapshot.stamp',
     'resources_cc_file': '<(gen_source_dir)/resources_gen.cc',
     'bootstrap_resources_cc_file':
         '<(gen_source_dir)/bootstrap_resources_gen.cc',
     'snapshot_cc_file': '<(gen_source_dir)/snapshot_gen.cc',
   },
   'targets': [
     {
       'target_name': 'generate_builtin_cc_file',
       'type': 'none',
       'toolsets':['host'],
@@ skipping 387 matching lines @@
         'gen_snapshot#host',
       ],
       'actions': [
         {
           'action_name': 'generate_snapshot_bin',
           'inputs': [
             '../tools/create_snapshot_bin.py',
             '<(PRODUCT_DIR)/<(EXECUTABLE_PREFIX)gen_snapshot<(EXECUTABLE_SUFFIX)',
           ],
           'outputs': [
-            '<(vm_isolate_snapshot_bin_file)',
-            '<(isolate_snapshot_bin_file)',
+            '<(gen_snapshot_stamp_file)',
           ],
           'action': [
             'python',
             'tools/create_snapshot_bin.py',
             '--executable',
             '<(PRODUCT_DIR)/<(EXECUTABLE_PREFIX)gen_snapshot<(EXECUTABLE_SUFFIX)',
             '--vm_output_bin', '<(vm_isolate_snapshot_bin_file)',
             '--output_bin', '<(isolate_snapshot_bin_file)',
-            '--target_os', '<(OS)'
+            '--target_os', '<(OS)',
+            '--timestamp_file', '<(gen_snapshot_stamp_file)',
           ],
           'message': 'Generating ''<(vm_isolate_snapshot_bin_file)'' ''<(isolate_snapshot_bin_file)'' files.'
         },
       ],
     },
     {
       # Generate snapshot file.
       'target_name': 'generate_snapshot_file',
       'type': 'none',
       'toolsets':['host'],
       'dependencies': [
         'generate_snapshot_bin#host',
       ],
       'actions': [
         {
           'action_name': 'generate_snapshot_file',
           'inputs': [
             '../tools/create_snapshot_file.py',
+            '<(gen_snapshot_stamp_file)',
             '<(snapshot_in_cc_file)',
-            '<(vm_isolate_snapshot_bin_file)',
-            '<(isolate_snapshot_bin_file)',
           ],
           'outputs': [
             '<(snapshot_cc_file)',
           ],
           'action': [
             'python',
             'tools/create_snapshot_file.py',
             '--vm_input_bin', '<(vm_isolate_snapshot_bin_file)',
             '--input_bin', '<(isolate_snapshot_bin_file)',
             '--input_cc', '<(snapshot_in_cc_file)',
@@ skipping 340 matching lines @@
         }],
         ['OS=="linux"', {
           'cflags': [
             '-fPIC',
           ],
         }],
       ],
     },
   ],
 }