--- jruby/lib/ruby/shared/rubygems/config_file.rb
+++ jrub-fix/lib/ruby/shared/rubygems/config_file.rb
@@ -25,6 +25,8 @@
 # +:sources+:: Sets Gem::sources
 # +:verbose+:: See #verbose
 
+require 'rbconfig'
+
 class Gem::ConfigFile
 
   DEFAULT_BACKTRACE = false
@@ -68,7 +70,7 @@
 
         path.strip
       rescue LoadError
-        "/etc"
+        RbConfig::CONFIG["sysconfdir"] || "/etc"
       end
     end
 
--- jruby/bin/jgem
+++ jruby-fix/bin/jgem
@@ -9,6 +9,15 @@
 # See LICENSE.txt for permissions.
 #++
 
+# The prelude in 1.9.1 injects rubygems.rb into $LOADED_FEATURES
+# which prevents the `require 'rubygems'` from actually loading
+# the site's version of rubygems. So we have to use it's API
+# to get it's prelude out of the way.
+#
+if RUBY_VERSION =~ /^1\.9\.1/ && defined?(Gem::QuickLoader)
+  Gem::QuickLoader.load_full_rubygems_library
+end
+
 require 'rubygems'
 require 'rubygems/gem_runner'
 require 'rubygems/exceptions'