part 2: latest gyp pointed at official git repo.

.gitmodules

@@ -13,3 +13,6 @@
 [submodule "third_party/xbyak"]
 	path = third_party/xbyak
 	url = https://github.com/herumi/xbyak.git
+[submodule "third_party/gyp"]
+	path = third_party/gyp
+	url = https://chromium.googlesource.com/external/gyp

third_party/gyp

@@ -0,0 +1 @@
+Subproject commit 867a23f4b596b7406cce1231a23b44b47bc1a583

third_party/gyp.patch

@@ -0,0 +1,26 @@
+diff --git a/pylib/gyp/generator/msvs.py b/pylib/gyp/generator/msvs.py
+index 05783d6..539614c 100644
+--- a/pylib/gyp/generator/msvs.py
++++ b/pylib/gyp/generator/msvs.py
+@@ -1963,13 +1963,17 @@ def _AppendFiltersForMSBuild(parent_filter_name, sources,
+     if isinstance(source, MSVSProject.Filter):
+       # We have a sub-filter.  Create the name of that sub-filter.
+       if not parent_filter_name:
+-        filter_name = source.name
++        if source.name == '..':
++          filter_name = ''
++        else:
++          filter_name = source.name
+       else:
+         filter_name = '%s\\%s' % (parent_filter_name, source.name)
+       # Add the filter to the group.
+-      filter_group.append(
+-          ['Filter', {'Include': filter_name},
+-           ['UniqueIdentifier', MSVSNew.MakeGuid(source.name)]])
++      if filter_name:
++        filter_group.append(
++            ['Filter', {'Include': filter_name},
++             ['UniqueIdentifier', MSVSNew.MakeGuid(source.name)]])
+       # Recurse and add its dependents.
+       _AppendFiltersForMSBuild(filter_name, source.contents,
+                                extension_to_rule_name,