2 files changed, 5 insertions, 0 deletions
diff --git a/lib/rubygems/ext/ext_conf_builder.rb b/lib/rubygems/ext/ext_conf_builder.rb
index d09cb5266f..70b57bd47b 100644
--- a/lib/rubygems/ext/ext_conf_builder.rb
+++ b/lib/rubygems/ext/ext_conf_builder.rb
@@ -37,6 +37,7 @@ class Gem::Ext::ExtConfBuilder < Gem::Ext::Builder
         run cmd, results
 
         ENV["DESTDIR"] = nil
+        siteconf.unlink
 
         make dest_path, results
 
diff --git a/lib/rubygems/psych_tree.rb b/lib/rubygems/psych_tree.rb
index eca8249383..e3f1d1a08a 100644
--- a/lib/rubygems/psych_tree.rb
+++ b/lib/rubygems/psych_tree.rb
@@ -1,6 +1,10 @@
 module Gem
   if defined? ::Psych::Visitors
     class NoAliasYAMLTree < Psych::Visitors::YAMLTree
+      def self.create
+        new({})
+      end unless respond_to? :create
+
       def visit_String(str)
         return super unless str == '=' # or whatever you want