Update the webpage (#3227)

JerryScript-DCO-1.0-Signed-off-by: Zsolt Borbély zsborbely.u-szeged@partner.samsung.com

05.PORT-API.md

@@ -93,10 +93,14 @@ information.
 void jerry_port_print_char (char c);
 ```
 
-### ES2015 Module system helper functions
+### ES2015 Module system
 
-The module system requires two specific functions for opening and closing files.
-It also requires a platform specific way of normalizing file paths.
+The port API provides functions that can be used by the module system to open
+and close source files, and normalize file paths.
+The `jerry_port_get_native_module` port function can be used to provide native
+modules to the engine. This function will be called when an import/export
+statement is encountered with an unknown module specifier, which embedders can
+use to supply native module objects based on the module name argument.
 
 ```c
 /**
@@ -136,6 +140,25 @@ jerry_port_normalize_path (const char *in_path_p, /**< input file path */
   // write to out_buf_p the normalized path
   // return length of written path
 } /* jerry_port_normalize_path */
+
+/**
+ * Get the module object of a native module.
+ *
+ * Note:
+ *      This port function is called by jerry-core when ES2015_MODULE_SYSTEM
+ *      is enabled.
+ *
+ * @param name String value of the module specifier.
+ *
+ * @return Undefined, if 'name' is not a native module
+ *         jerry_value_t containing the module object, otherwise
+ */
+jerry_value_t
+jerry_port_get_native_module (jerry_value_t name) /**< module specifier */
+{
+  (void) name;
+  return jerry_create_undefined ();
+}
 ```
 
 ## Date