ninja: Write gypcmd files into the output directory instead of the tree.

pylib/gyp/__init__.py

Index: pylib/gyp/__init__.py
===================================================================
--- pylib/gyp/__init__.py	(revision 1761)
+++ pylib/gyp/__init__.py	(working copy)
@@ -119,6 +119,8 @@
                 'generator_wants_static_library_dependencies_adjusted', True),
     'generator_wants_sorted_dependencies':
         getattr(generator, 'generator_wants_sorted_dependencies', False),
+    'generator_filelist_path':
+        getattr(generator, 'generator_filelist_path', None),
   }
 
   # Process the input specific to this generator.