diff --git a/.gitignore b/.gitignore
index e97ca2fe..65492a94 100644
--- a/.gitignore
+++ b/.gitignore
@@ -12,5 +12,6 @@
 *.so
 *.o
 *.a
+*.gem
 mkmf.log
 vendor/bundle
diff --git a/.gitmodules b/.gitmodules
index 1d1b46ab..e762dbbd 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,3 +1,3 @@
 [submodule "ext/libsass"]
 	path = ext/libsass
-  url = git://github.com/sass/libsass.git
+	url = https://github.com/sass/libsass.git
diff --git a/README.md b/README.md
index 31083f6b..5830be1e 100644
--- a/README.md
+++ b/README.md
@@ -6,7 +6,7 @@ This gem combines the speed of `libsass`, the [Sass C implementation](https://gi
 
 ### libsass Version
 
-[3.5.2](https://github.com/sass/libsass/releases/tag/3.5.2)
+[d225a09a](https://github.com/sass/libsass/commit/d225a09a152050d569c077f97bb944c8dc819d6f)
 
 ## Installation
 
diff --git a/Rakefile b/Rakefile
index 13e97e8a..f682dc4e 100644
--- a/Rakefile
+++ b/Rakefile
@@ -1,15 +1,30 @@
-begin
-  require 'bundler/gem_tasks'
-rescue LoadError
-  puts 'Cannot load bundler/gem_tasks'
-end
-
-require 'tasks/libsass'
+require 'bundler/gem_tasks'
 
 task default: :test
 
+require 'rake/extensiontask'
+gem_spec = Gem::Specification.load("sassc.gemspec")
+Rake::ExtensionTask.new('libsass', gem_spec) do |ext|
+  ext.name = 'libsass'
+  ext.ext_dir = 'ext'
+  ext.lib_dir = 'lib/sassc'
+  ext.cross_compile = true
+  ext.cross_platform = %w[x86-mingw32 x64-mingw32 x86-linux x86_64-linux]
+  ext.cross_compiling do |spec|
+    spec.files.reject! { |path| File.fnmatch?('ext/*', path) }
+  end
+end
+
+desc 'Compile all native gems via rake-compiler-dock (Docker)'
+task 'gem:native' do
+  require 'rake_compiler_dock'
+  RakeCompilerDock.sh "bundle && gem i rake --no-document && "\
+                      "rake cross native gem MAKE='nice make -j`nproc`' "\
+                      "RUBY_CC_VERSION=2.6.0:2.5.0:2.4.0:2.3.0"
+end
+
 desc "Run all tests"
-task test: 'libsass:compile' do
+task test: 'compile:libsass' do
   $LOAD_PATH.unshift('lib', 'test')
   Dir.glob('./test/**/*_test.rb') { |f| require f }
 end
diff --git a/ext/Rakefile b/ext/Rakefile
deleted file mode 100644
index a8ed3958..00000000
--- a/ext/Rakefile
+++ /dev/null
@@ -1,3 +0,0 @@
-require_relative '../lib/tasks/libsass'
-
-task default: 'libsass:compile'
diff --git a/ext/extconf.rb b/ext/extconf.rb
new file mode 100644
index 00000000..adbb065c
--- /dev/null
+++ b/ext/extconf.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+gem_root = File.expand_path('..', __dir__)
+libsass_dir = File.join(gem_root, 'ext', 'libsass')
+
+if !File.directory?(libsass_dir) ||
+   # '.', '..', and possibly '.git' from a failed checkout:
+   Dir.entries(libsass_dir).size <= 3
+  Dir.chdir(gem_root) { system('git submodule update --init') } or
+    fail 'Could not fetch libsass'
+end
+
+File.write 'Makefile', <<-MAKEFILE
+ifndef DESTDIR
+	LIBSASS_OUT = #{gem_root}/lib/sassc/libsass.so
+else
+	LIBSASS_OUT = $(DESTDIR)$(PREFIX)/libsass.so
+endif
+
+SUB_DIR := #{libsass_dir}
+SUB_TARGET := lib/libsass.so
+
+libsass.so:#{' clean' if ENV['CLEAN']}
+	$(MAKE) -C '$(SUB_DIR)' lib/libsass.so
+	cp '$(SUB_DIR)/lib/libsass.so' libsass.so
+	strip libsass.so
+
+install: libsass.so
+	cp libsass.so '$(LIBSASS_OUT)'
+
+clean:
+	$(MAKE) -C '$(SUB_DIR)' clean
+	rm -f '$(LIBSASS_OUT)' libsass.so
+
+.PHONY: clean install
+MAKEFILE
diff --git a/ext/libsass b/ext/libsass
index 9cfe0df9..8d220b74 160000
--- a/ext/libsass
+++ b/ext/libsass
@@ -1 +1 @@
-Subproject commit 9cfe0df975945325e05d6dd39ee98224898d9a79
+Subproject commit 8d220b74770ad16aaf7819b5e18d85746aa63d7d
diff --git a/lib/sassc/engine.rb b/lib/sassc/engine.rb
index 150ce022..935b547d 100644
--- a/lib/sassc/engine.rb
+++ b/lib/sassc/engine.rb
@@ -133,7 +133,7 @@ def output_style
 
     def load_paths
       paths = (@options[:load_paths] || []) + SassC.load_paths
-      paths.join(":") if paths.any?
+      paths.join(File::PATH_SEPARATOR) unless paths.empty?
     end
   end
 end
diff --git a/lib/sassc/native.rb b/lib/sassc/native.rb
index 443dcbe1..b9ed8f1c 100644
--- a/lib/sassc/native.rb
+++ b/lib/sassc/native.rb
@@ -8,7 +8,13 @@ module Native
 
     spec = Gem.loaded_specs["sassc"]
     gem_root = spec.gem_dir
-    ffi_lib "#{gem_root}/ext/libsass/lib/libsass.so"
+
+    ruby_version_so_path = "#{gem_root}/lib/sassc/#{RUBY_VERSION[/\d+.\d+/]}/libsass.so"
+    if File.exist?(ruby_version_so_path)
+      ffi_lib ruby_version_so_path
+    else
+      ffi_lib "#{gem_root}/lib/sassc/libsass.so"
+    end
 
     require_relative "native/sass_value"
 
diff --git a/lib/tasks/libsass.rb b/lib/tasks/libsass.rb
deleted file mode 100644
index 57ed47bd..00000000
--- a/lib/tasks/libsass.rb
+++ /dev/null
@@ -1,33 +0,0 @@
-# frozen_string_literal: true
-
-namespace :libsass do
-  desc "Compile libsass"
-  task :compile do
-    if Dir.pwd.end_with?('/ext')
-      libsass_path = "libsass"
-    else
-      libsass_path = "ext/libsass"
-    end
-
-    cd libsass_path do
-      Rake::Task["lib/libsass.so"].invoke
-    end
-  end
-
-  file "Makefile" do
-    sh "git submodule update --init"
-  end
-
-  file "lib/libsass.so" => "Makefile" do
-    make_program = ENV['MAKE']
-    make_program ||= case RUBY_PLATFORM
-                     when /mswin/
-                       'nmake'
-                     when /(bsd|solaris)/
-                       'gmake'
-                     else
-                       'make'
-                     end
-    sh "#{make_program} lib/libsass.so"
-  end
-end
diff --git a/sassc.gemspec b/sassc.gemspec
index b92366f1..f2ea18b3 100644
--- a/sassc.gemspec
+++ b/sassc.gemspec
@@ -23,26 +23,34 @@ Gem::Specification.new do |spec|
 
   spec.require_paths = ["lib"]
 
-  spec.extensions    = ["ext/Rakefile"]
+  spec.platform      = Gem::Platform::RUBY
+  spec.extensions    = ["ext/extconf.rb"]
 
   spec.add_development_dependency "minitest", "~> 5.5.1"
   spec.add_development_dependency "minitest-around"
   spec.add_development_dependency "test_construct"
   spec.add_development_dependency "pry"
   spec.add_development_dependency "bundler"
+  spec.add_development_dependency "rake"
+  spec.add_development_dependency "rake-compiler"
+  spec.add_development_dependency "rake-compiler-dock"
 
-  spec.add_dependency "rake"
   spec.add_dependency "ffi", "~> 1.9"
 
   gem_dir = File.expand_path(File.dirname(__FILE__)) + "/"
-  `git submodule --quiet foreach pwd`.split($\).each do |submodule_path|
-    Dir.chdir(submodule_path) do
-      submodule_relative_path = submodule_path.sub gem_dir, ""
-      # issue git ls-files in submodule's directory and
-      # prepend the submodule path to create absolute file paths
-      `git ls-files`.split($\).each do |filename|
-        spec.files << "#{submodule_relative_path}/#{filename}"
-      end
+
+  libsass_dir = File.join(gem_dir, 'ext', 'libsass')
+  if !File.directory?(libsass_dir)
+    $stderr.puts "Error: ext/libsass not checked out. Please run:\n\n"\
+                 "  git submodule update --init"
+    exit 1
+  end
+
+  Dir.chdir(libsass_dir) do
+    submodule_relative_path = File.join('ext', 'libsass')
+    `git ls-files`.split($\).each do |filename|
+      next if filename =~ %r{(^("?test|docs|script)/)|\.md$|\.yml$}
+      spec.files << File.join(submodule_relative_path, filename)
     end
   end
 
diff --git a/test/engine_test.rb b/test/engine_test.rb
index 6169e5cf..a273efee 100644
--- a/test/engine_test.rb
+++ b/test/engine_test.rb
@@ -88,7 +88,7 @@ def test_precision_not_specified
 SCSS
       expected_output = <<-CSS
 .foo {
-  baz: 0.33333; }
+  baz: 0.3333333333; }
 CSS
       output = Engine.new(template).render
       assert_equal expected_output, output
@@ -218,7 +218,7 @@ def test_global_load_paths
     def test_env_load_paths
       expected_load_paths = [ "included_1", "included_2" ]
       ::SassC.instance_eval { @load_paths = nil }
-      ENV['SASS_PATH'] = expected_load_paths.join(':')
+      ENV['SASS_PATH'] = expected_load_paths.join(File::PATH_SEPARATOR)
       assert_equal expected_load_paths, ::SassC.load_paths
       ::SassC.load_paths.clear
     end
diff --git a/test/native_test.rb b/test/native_test.rb
index 639e0e7c..8937ea03 100644
--- a/test/native_test.rb
+++ b/test/native_test.rb
@@ -11,7 +11,7 @@ module NativeTest
 
     class General < MiniTest::Test
       def test_it_reports_the_libsass_version
-        assert_equal "3.5.2", Native.version
+        assert_equal "3.6.0", Native.version
       end
     end