fix using sysconfdir for 1.8.x rubies

[mpapis]

for the line of rubies 1.8 rubygems did not load sysconfdir and defaulted back to /etc which lead to problems like this: https://gist.github.com/1981223

[mpapis]

@djberg96 that would work via two exceptions, I have changed code to use first RbConfig::CONFIG['sysconfdir'] which should be the primary source of sysconfdir (at least for 1.8)

[mpapis]

to keep cross references https://bugs.ruby-lang.org/issues/6121

[bearded]

$ git checkout origin/1.8 -b 1.8 Branch 1.8 set up to track remote branch 1.8 from origin. Switched to a new branch '1.8' 

$ ruby setup.rb RubyGems 1.8.18 installed == 1.8.18 / 2012-03-11 * 4 bug fixes: * Use Psych API to emit more compatible YAML * Download and write inside `gem fetch` directly. Fixes #289 * Honor sysconfdir on 1.8. Fixes #291 * Search everywhere for a spec for `gem spec`. Fixes #288 * Fix Gem.all_load_path. Fixes #171 ------------------------------------------------------------------------------ RubyGems installed the following executables: /usr/local/rvm/rubies/ruby-1.9.1-p431/bin/gem 

$ gem -v /usr/local/rvm/rubies/ruby-1.9.1-p431/lib/ruby/site_ruby/1.9.1/rubygems/config_file.rb:71:in `rescue in rescue in <class:ConfigFile>': uninitialized constant Gem::ConfigFile::RbConfig (NameError) from /usr/local/rvm/rubies/ruby-1.9.1-p431/lib/ruby/site_ruby/1.9.1/rubygems/config_file.rb:53:in `rescue in <class:ConfigFile>' from /usr/local/rvm/rubies/ruby-1.9.1-p431/lib/ruby/site_ruby/1.9.1/rubygems/config_file.rb:49:in `<class:ConfigFile>' from /usr/local/rvm/rubies/ruby-1.9.1-p431/lib/ruby/site_ruby/1.9.1/rubygems/config_file.rb:28:in `<top (required)>' from /usr/local/rvm/rubies/ruby-1.9.1-p431/lib/ruby/site_ruby/1.9.1/rubygems/gem_runner.rb:9:in `require' from /usr/local/rvm/rubies/ruby-1.9.1-p431/lib/ruby/site_ruby/1.9.1/rubygems/gem_runner.rb:9:in `<top (required)>' from /usr/local/rvm/rubies/ruby-1.9.1-p431/bin/gem:9:in `require' from /usr/local/rvm/rubies/ruby-1.9.1-p431/bin/gem:9:in `<main>' 

[mpapis]

this might be because there is no explicit require "rbconfig" in the fix like it was in mine proposed code ...

[bearded]

@mpapis, yes, require "rbconfig" solves this problem, and gem -v works on 1.8.7, 1.9.1, 1.9.2 and 1.9.3