Fix gyp build.

tools/gyp/v8.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 13 matching lines @@
 # 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': {
     'icu_use_data_file_flag%': 0,
     'v8_code': 1,
     'v8_random_seed%': 314159265,
     'v8_vector_stores%': 0,
-    'embed_script%': "-",
-    'warmup_script%': "-",
+    'embed_script%': "",
+    'warmup_script%': "",
     'v8_extra_library_files%': [],
     'v8_experimental_extra_library_files%': [],
     'mksnapshot_exec': '<(PRODUCT_DIR)/<(EXECUTABLE_PREFIX)mksnapshot<(EXECUTABLE_SUFFIX)',
   },
   'includes': ['../../build/toolchain.gypi', '../../build/features.gypi'],
   'targets': [
     {
       'target_name': 'v8',
       'dependencies_traverse': 1,
       'dependencies': ['v8_maybe_snapshot'],
@@ skipping 2231 matching lines @@
         }],
         ['want_separate_host_toolset==1', {
           'toolsets': ['host'],
         }, {
           'toolsets': ['target'],
         }],
       ],
     },
   ],
 }