Add basic support for compile-time options via a yaml file

.gitignore

@@ -1,4 +1,7 @@
 .DS_Store
 tmp
 pkg
-testing/Gemfile
+testing/Gemfile
+spec/fixtures/very-simple-binary/ext/Makefile
+spec/fixtures/very-simple-binary/ext/very-simple-binary.o
+spec/fixtures/very-simple-binary/ext/very_simple_binary.bundle

lib/bundler/commands/bundle_command.rb

@@ -26,6 +26,12 @@ def initialize
     add_option('--list', "List all gems that are part of the active bundle") do
       options[:list] = true
     end
+
+    add_option('-b', '--build-options OPTION_FILE', "Specify a path to a yml file with build options for binary gems") do |option_file, options|
+      if File.exist?(option_file)
+        options[:build_options] = YAML.load_file(option_file)
+      end
+    end
   end
 
   def usage

lib/bundler/environment.rb

@@ -53,12 +53,13 @@ def install(options = {})
       no_bundle = dependencies.select { |dep| !dep.bundle }
 
       repository.install(gem_dependencies, sources,
-        :rubygems    => rubygems,
-        :system_gems => system_gems,
-        :manifest    => filename,
-        :update      => update,
-        :cached      => cached,
-        :no_bundle   => no_bundle.map { |dep| dep.name }
+        :rubygems      => rubygems,
+        :system_gems   => system_gems,
+        :manifest      => filename,
+        :update        => update,
+        :cached        => cached,
+        :build_options => options[:build_options],
+        :no_bundle     => no_bundle.map { |dep| dep.name }
       )
       Bundler.logger.info "Done."
     end

lib/bundler/repository.rb

@@ -135,6 +135,10 @@ def expand_gemfile(spec, options)
 
       gemfile = @path.join("cache", "#{spec.full_name}.gem").to_s
 
+      if build_args = options[:build_options][spec.name]
+        Gem::Command.build_args = build_args.map {|k,v| "--with-#{k}=#{v}"}
+      end
+
       installer = Gem::Installer.new(gemfile, options.merge(
         :install_dir         => @path,
         :ignore_dependencies => true,
@@ -143,6 +147,8 @@ def expand_gemfile(spec, options)
         :bin_dir             => @bindir
       ))
       installer.install
+    ensure
+      Gem::Command.build_args = []
     end
 
     def expand_vendored_gem(spec, options)

spec/bundler/cli_spec.rb

@@ -1,6 +1,49 @@
 require File.expand_path(File.dirname(__FILE__) + '/../spec_helper')
 
 describe "Bundler::CLI" do
+  describe "it compiles gems that take options" do
+    before(:each) do
+      build_manifest <<-Gemfile
+        clear_sources
+        source "file://#{gem_repo1}"
+        gem "very-simple-binary"
+      Gemfile
+    end
+
+    it "fails if the option is not provided" do
+      Dir.chdir(bundled_app) do
+        output = gem_command :bundle, "2>&1"
+      end
+
+      output.should =~ /Failed to build gem native extension/
+    end
+
+    it "passes if a yaml is specified that contains the necessary options" do
+      File.open(bundled_app.join("build.yml"), "w+") do |file|
+        file.puts <<-build_options.gsub(/^          /, '')
+          very-simple-binary:
+            simple: wot
+        build_options
+      end
+
+      Dir.chdir(bundled_app) do
+        @output = gem_command :bundle, "--build-options=build.yml 2>&1"
+      end
+
+      @output.should_not =~ /Failed to build gem native extension/
+
+      ruby_code = <<-RUBY.split("\n").join("; ")
+        require %{very_simple_binary}
+        include VerySimpleBinaryForTests
+        puts working
+      RUBY
+
+      @output = run_in_context "exec %{#{Gem.ruby} -e '#{ruby_code}'}"
+
+      @output.should == "true"
+    end
+  end
+
   describe "it working" do
     before(:each) do
       build_manifest <<-Gemfile