merge revision(s) 39542,39545: [Backport #7991]

	* lib/rubygems/ext/builder.rb:  Fix incompatibilities when installing
	  extensions.  Patch by Nobu.
	  [ruby-trunk - Bug #7968] [ruby-trunk - Bug #7971]

	* lib/rubygems/ext/ext_conf_builder.rb:  ditto.

	* lib/rubygems/installer.rb:  ditto.

	* test/rubygems/test_gem_ext_ext_conf_builder.rb:  Test for the above.

	* test/rubygems/test_gem_installer.rb:  ditto.

	* lib/rubygems/commands/sources_command.rb:  Prefer HTTPS over HTTP.

	* lib/rubygems/defaults.rb:  ditto

	* lib/rubygems/dependency_resolver.rb:  Ditto.

	* lib/rubygems/source.rb:  ditto.

	* lib/rubygems/spec_fetcher.rb:  ditto.

	* lib/rubygems/specification.rb:  ditto.

	* lib/rubygems/test_utilities.rb:  ditto.

	* test/rubygems/test_gem.rb:  Test for the above.

	* test/rubygems/test_gem_commands_sources_command.rb:  ditto.

	* test/rubygems/test_gem_dependency_resolver_api_set.rb:  ditto.

	* test/rubygems/test_gem_remote_fetcher.rb:  ditto.

	* test/rubygems/test_gem_source.rb:  ditto.

	* test/rubygems/test_gem_spec_fetcher.rb:  ditto.
	  [ruby-trunk - Bug #7698] [ruby-trunk - Bug #7971]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_0_0@39786 b2dd03c8-39d4-4d8f-98ff-823fe69b080e