Enable LTO and -march=native

-march=native is only enabled when not cross-compiling

Rakefile

@@ -14,6 +14,8 @@ Rake::ExtensionTask.new('libsass', gem_spec) do |ext|
   # Link C++ stdlib statically when building binary gems.
   ext.cross_config_options << '--enable-static-stdlib'
 
+  ext.cross_config_options << '--disable-march-native'
+
   ext.cross_compiling do |spec|
     spec.files.reject! { |path| File.fnmatch?('ext/*', path) }
 

ext/extconf.rb

@@ -14,11 +14,23 @@
 
 $CXXFLAGS << ' -std=c++11'
 
-# Link stdlib statically when building binary gems.
-if enable_config('static-stdlib')
+# Set to true when building binary gems
+if enable_config('static-stdlib', false)
   $LDFLAGS << ' -static-libgcc -static-libstdc++'
 end
 
+# Set to false when building binary gems
+if enable_config('march-native', true)
+  $CFLAGS << ' -march=native'
+  $CXXFLAGS << ' -march=native'
+end
+
+if enable_config('lto', true)
+  $CFLAGS << ' -flto'
+  $CXXFLAGS << ' -flto'
+  $LDFLAGS << ' -flto'
+end
+
 # Disable noisy compilation warnings.
 $warnflags = ''
 $CFLAGS.gsub!(/[\s+](-ansi|-std=[^\s]+)/, '')