Support for Internationalized Domain Names (IDN)

https://github.com/FreshRSS/FreshRSS/issues/819
Add explicit conversion from IDN to Punycode.

Requires PHP 5.3 IDN extension http://php.net/intl.idn (php5-idn package
on Debian/Ubuntu).

For systems without PHP 5.3+ IDN extension, we may consider adding a
dependency (322 kB) to the third-party library
https://phlymail.com/en/downloads/idna-convert.html

See PHP bug 53474 FILTER_VALIDATE_URL should not fail URL's that use
IDNhttps://bugs.php.net/bug.php?id=53474

1 files changed, 1 insertions, 1 deletions

diff --git a/README.md b/README.md
index a09a64639..92072b07d 100644
--- a/README.md
+++ b/README.md
@@ -32,7 +32,7 @@ The best way is to open issues on GitHub
 	* It even works on Raspberry Pi with response time under a second (tested with 150 feeds, 22k articles, or 32Mo of compressed data)
 * A web server: Apache2 (recommanded), nginx, lighttpd (not tested on others)
 * PHP 5.2.1+ (PHP 5.3.7+ recommanded)
-	* Required extensions: [PDO_MySQL](http://php.net/pdo-mysql) or [PDO_SQLite](http://php.net/pdo-sqlite), [cURL](http://php.net/curl), [GMP](http://php.net/gmp) (only for API access on platforms under 64 bits)
+	* Required extensions: [PDO_MySQL](http://php.net/pdo-mysql) or [PDO_SQLite](http://php.net/pdo-sqlite), [cURL](http://php.net/curl), [GMP](http://php.net/gmp) (for API access on platforms < 64 bits), [IDN](http://php.net/intl.idn) (for Internationalized Domain Names)
 	* Recommanded extensions : [JSON](http://php.net/json), [mbstring](http://php.net/mbstring), [zlib](http://php.net/zlib), [Zip](http://php.net/zip)
 * MySQL 5.0.3+ (recommanded) or SQLite 3.7.4+
 * A recent browser like Firefox 4+, Chrome, Opera, Safari, Internet Explorer 9+