build

# File lib/rubygems/ext/ext_conf_builder.rb, line 13
  def self.build(extension, directory, dest_path, results, args=[], lib_dir=nil)
    tmp_dest = Dir.mktmpdir(".gem.", ".")

    t = nil
    Tempfile.open %siteconf .rb", "." do |siteconf|
      t = siteconf
      siteconf.puts "require 'rbconfig'"
      siteconf.puts "dest_path = #{(tmp_dest || dest_path).dump}"
      ]sitearchdir sitelibdir].each do |dir|
        siteconf.puts "RbConfig::MAKEFILE_CONFIG['#{dir}'] = dest_path"
        siteconf.puts "RbConfig::CONFIG['#{dir}'] = dest_path"
      end

      siteconf.flush

      siteconf_path = File.expand_path siteconf.path

      rubyopt = ENV["RUBYOPT"]
      destdir = ENV["DESTDIR"]

      begin
        ENV["RUBYOPT"] = ["-r#{siteconf_path}", rubyopt].compact.join(' ')
        cmd = [Gem.ruby, File.basename(extension), *args].join ' '

        begin
          run cmd, results
        ensure
          FileUtils.mv 'mkmf.log', dest_path if File.exist? 'mkmf.log'
        end

        ENV["DESTDIR"] = nil
        ENV["RUBYOPT"] = rubyopt
        siteconf.unlink

        make dest_path, results

        if tmp_dest
          # TODO remove in RubyGems 3
          if Gem.install_extension_in_lib and lib_dir then
            FileUtils.mkdir_p lib_dir
            entries = Dir.entries(tmp_dest) - ]. ..]
            entries = entries.map { |entry| File.join tmp_dest, entry }
            FileUtils.cp_r entries, lib_dir
          end

          FileEntry.new(tmp_dest).traverse do |ent|
            destent = ent.class.new(dest_path, ent.rel)
            destent.exist? or File.rename(ent.path, destent.path)
          end
        end
      ensure
        ENV["RUBYOPT"] = rubyopt
        ENV["DESTDIR"] = destdir
      end
    end
    t.unlink if t and t.path

    results
  ensure
    FileUtils.rm_rf tmp_dest if tmp_dest
  end