[PodTargetInstaller] Write custom module maps using a generator

lib/cocoapods/installer/xcode/pods_project_generator/pod_target_installer.rb

@@ -614,19 +614,15 @@ module Pod
 
           def create_module_map
             return super unless custom_module_map
+
             path = target.module_map_path
-            path.mkpath
             UI.message "- Copying module map file to #{UI.path(path)}" do
-              Tempfile.open(path.basename.to_s) do |tmp_module_map|
               contents = custom_module_map.read
               unless target.requires_frameworks?
                 contents.gsub!(/^(\s*)framework\s+module/, '\1module')
               end
-                tmp_module_map.write contents
-                tmp_module_map.rewind
-                unless path.exist? && FileUtils.identical?(tmp_module_map, path)
-                  FileUtils.cp(tmp_module_map, path)
-                end
+              generator = Generator::Constant.new(contents)
+              update_changed_file(generator, path)
               add_file_to_support_group(path)
 
               native_target.build_configurations.each do |c|
@@ -635,7 +631,6 @@ module Pod
               end
             end
           end
-          end
 
           def module_map_additional_headers
             return [] unless umbrella_headers_by_dir