add a sanity check for CURL when using pubsubhubbub

config.php-dist

@@ -188,14 +188,14 @@
 	// Your OAuth instance authentication information for Twitter, visit
 	// http://twitter.com/oauth_clients to register your instance.
 
-	define('ISCONFIGURED', false);
-	// Please set this to true if you have read everything above and
-	// finished setting configuration options.
-
 	define('PUBSUBHUBBUB_HUB', '');
 	// URL to a PubSubHubbub-compatible hub server. If defined, Published
 	// articles generated feeds would automatically become PUSH-enabled.
 
+	define('ISCONFIGURED', false);
+	// Please set this to true if you have read everything above and
+	// finished setting configuration options.
+
 	define('CONFIG_VERSION', 22);
 	// Expected config version. Please update this option in config.php
 	// if necessary (after migrating all new options from this file).

sanity_check.php

@@ -143,6 +143,10 @@
 		$err_msg = "php.ini: Safe mode is not supported. If you wish to continue, remove this test from sanity_check.php and proceeed at your own risk. Please note that your bug reports will not be accepted or reviewed.";
 	}
 
+	if (PUBSUBHUBBUB_HUB && !function_exists("curl_init")) {
+		$err_msg = "PUBSUBHUBBUB_HUB is defined, but CURL functions are not found. CURL is required for PubSubHubbub support.";
+	}
+
 	if ($err_msg) {
 		print "<b>Fatal Error</b>: $err_msg\n";
 		exit;