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

pylib/gyp/input.py

Index: pylib/gyp/input.py
===================================================================
--- pylib/gyp/input.py	(revision 1758)
+++ pylib/gyp/input.py	(working copy)
@@ -781,7 +781,7 @@
       # Find the build file's directory, so commands can be run or file lists
       # generated relative to it.
       build_file_dir = os.path.dirname(build_file)
-      if build_file_dir == '':
+      if build_file_dir == '' and not file_list:
         # If build_file is just a leaf filename indicating a file in the
         # current directory, build_file_dir might be an empty string.  Set
         # it to None to signal to subprocess.Popen that it should run the
@@ -798,9 +798,11 @@
       else:
         contents_list = contents.split(' ')
       replacement = contents_list[0]
-      path = replacement
-      if build_file_dir and not os.path.isabs(path):
-        path = os.path.join(build_file_dir, path)
+      if os.path.isabs(replacement):
+        raise GypError('| cannot handle absolute paths, got "%s"' % path)
+
+      path = generator_filelist_path(build_file_dir, replacement)
+      replacement = gyp.common.RelativePath(path, build_file_dir)
       f = gyp.common.WriteOnDiff(path)
       for i in contents_list[1:]:
         f.write('%s\n' % i)
@@ -2599,6 +2601,11 @@
   multiple_toolsets = generator_input_info[
       'generator_supports_multiple_toolsets']
 
+  global generator_filelist_path
+  generator_filelist_path = generator_input_info['generator_filelist_path']
+  if not generator_filelist_path:
+    generator_filelist_path = lambda a, b: os.path.join(a, b)
+
   # A generator can have other lists (in addition to sources) be processed
   # for rules.
   extra_sources_for_rules = generator_input_info['extra_sources_for_rules']