merge revision(s) 39579: [Backport #7991]
* lib/rubygems/ext/ext_conf_builder.rb (Gem::Ext::ExtConfBuilder.build): fix for unusal cases again. install to a temporary directory once and move instaled files to the destination directory, if it is same as the current directory. [Bug #7698]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_0_0@39791 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
merge revision(s) 39579: [Backport #7991]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_0_0@39791 b2dd03c8-39d4-4d8f-98ff-823fe69b080e