add some basic "did I forget to create config.php" sanity checks

backend.php

@@ -22,6 +22,7 @@
 
 	define(SCHEMA_VERSION, 2);
 
+	require_once "sanity_check.php";
 	require_once "config.php";
 	require_once "db.php";
 	require_once "db-prefs.php";

error.php

@@ -1,4 +1,5 @@
 <?
+	require_once "sanity_check.php";
 	require_once "version.php";
 	require_once "config.php";
 	require_once "db-prefs.php";

login.php

@@ -1,6 +1,7 @@
 <?
 	session_start();
 
+	require_once "sanity_check.php";
 	require_once "version.php"; 
 	require_once "config.php";
 	require_once "functions.php";

opml.php

@@ -1,6 +1,8 @@
 <?
 	session_start();
 
+	require_once "sanity_check.php";
+
 	// FIXME there are some brackets issues here
 
 	$op = $_REQUEST["op"];

prefs.php

@@ -1,6 +1,7 @@
 <?
 	session_start();
 
+	require_once "sanity_check.php";
 	require_once "version.php"; 
 	require_once "config.php";
 	require_once "db-prefs.php";

sanity_check.php

@@ -0,0 +1,15 @@
+<?
+	if (!file_exists("config.php")) {
+		print "<b>Fatal Error</b>: You forgot to copy 
+		<b>config.php-dist</b> to <b>config.php</b> and edit it.";
+		exit;
+	}
+
+	if (!file_exists("magpierss/rss_fetch.inc")) {
+		print "<b>Fatal Error</b>: You forgot to place 
+		<a href=\"http://magpierss.sourceforge.net\">MagpieRSS</a>
+		distribution in <b>magpierss/</b>
+		subdirectory of TT-RSS tree.";
+		exit;
+	}
+?>

tt-rss.php

@@ -1,6 +1,7 @@
 <?
 	session_start();
 
+	require_once "sanity_check.php";
 	require_once "version.php"; 
 	require_once "config.php";
 	require_once "db-prefs.php";