Merge pull request #1157 from FishNeil/master

Fix the project generation issue in vs2012.py.

tools/vs2012.py

@@ -134,7 +134,7 @@ def VS_add_HeadFiles(program, elem, project_path):
     ItemGroup = SubElement(elem, 'ItemGroup')
 
     filter_h_ItemGroup = SubElement(filter_project, 'ItemGroup')
-    for f in building.source_list:
+    for f in utils.source_list:
         path = _make_path_relative(project_path, f)
         File = SubElement(ItemGroup, 'ClInclude')
         File.set('Include', path.decode(fs_encoding))