Use idn_to_ascii function instead of idna_convert library

CHANGELOG.md

@@ -7,6 +7,14 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased](https://github.com/simplepie/simplepie/compare/1.8.0...master)
 
+### Changed
+
+- Use `idn_to_ascii` function instead of `idna_convert` library (requires `intl` extension or a [polyfill](https://github.com/symfony/polyfill-intl-idn)) by @jtojnar in [#785](https://github.com/simplepie/simplepie/pull/785)
+
+### Removed
+
+- Third-party `idna_convert` library is no longer part of the repository by @jtojnar in [#785](https://github.com/simplepie/simplepie/pull/785)
+
 ### Deprecated
 
 - Passing multiple URLs to `SimplePie\SimplePie::set_feed_url()` is deprecated. You can create separate `SimplePie` instance per feed and then use `SimplePie::merge_items()` to get a single list of items. ([#795](https://github.com/simplepie/simplepie/pull/795))

README.markdown

@@ -14,6 +14,7 @@ Requirements
 * PHP 7.2+ (Required since SimplePie 1.8.0)
 * libxml2 (certain 2.7.x releases are too buggy for words, and will crash)
 * One of iconv, mbstring or intl extensions
+* Optionally, intl extension, [symfony/polyfill-intl-idn](https://github.com/symfony/polyfill-intl-idn) or cURL extension built with IDN support to support IDNs
 * cURL or fsockopen()
 * PCRE support
 
@@ -29,10 +30,8 @@ What comes in the package?
    server for required settings.
 6. `demo/` - A basic feed reader demo that shows off some of SimplePie's more
    noticeable features.
-7. `idn/` - A third-party library that SimplePie can optionally use to
-   understand Internationalized Domain Names (IDNs).
-8. `build/` - Scripts related to generating pieces of SimplePie
-9. `test/` - SimplePie's unit test suite.
+7. `build/` - Scripts related to generating pieces of SimplePie
+8. `test/` - SimplePie's unit test suite.
 
 ### Where's `simplepie.inc`?
 Since SimplePie 1.3, we've split the classes into separate files to make it easier

demo/index.php

@@ -6,7 +6,6 @@
 // Include SimplePie
 // Located in the parent directory
 include_once('../autoloader.php');
-include_once('../idn/idna_convert.class.php');
 
 // Create a new instance of the SimplePie object
 $feed = new \SimplePie\SimplePie();

demo/test.php

@@ -1,6 +1,5 @@
 <?php
 include_once('../autoloader.php');
-include_once('../idn/idna_convert.class.php');
 
 // Parse it
 $feed = new \SimplePie\SimplePie();