Fix #14: get_magic_quotes_gpc() is removed as of PHP 8.0.0

Since the plugin currently might still support PHP 5.3, we need to
support the dreaded magic_quotes, so we work around by checking if
the function is defined.

admin.php

@@ -864,7 +864,7 @@ function sourceView($file,$template=0)
     $action = isset($_POST['action']) ? $_POST['action']  : '';
     $savedfile = isset($_POST['file']) ? $_POST['file']  : '';
     $data = isset($_POST['data']) ? $_POST['data']  : '';
-    if(get_magic_quotes_gpc()) $data = stripslashes($data);
+    if(function_exists("get_magic_quotes_gpc") && get_magic_quotes_gpc()) $data = stripslashes($data);
     $data = str_replace('¬','­',$data);
 
     // check if the new filename has unwanted characters

includes/calendarconfig.php

@@ -132,7 +132,7 @@
     // css-values
     //=============
     $nowrapdata         = $nowrap? 'nowrap' : 'normal';
-    if(get_magic_quotes_gpc()) {
+    if(function_exists("get_magic_quotes_gpc") && get_magic_quotes_gpc()) {
         $headlineconfig     = "\n" . trim(stripslashes($headlineconfig))  . "\n";
         $daynameconfig      = "\n" . trim(stripslashes($daynameconfig))   . "\n";
         $todaynameconfig    = "\n" . trim(stripslashes($todaynameconfig)) . "\n";

includes/eventlistconfig.php

@@ -68,7 +68,7 @@
 $monthfontsize   = isset($_POST['monthfontsize'])   ? $_POST['monthfontsize']   : $monthfontsize;
 $eventfontweight = isset($_POST['eventfontweight']) ? $_POST['eventfontweight'] : $eventfontweight;
 
-if(get_magic_quotes_gpc()) $eventlistpage = stripslashes($eventlistpage);
+if(function_exists("get_magic_quotes_gpc") && get_magic_quotes_gpc()) $eventlistpage = stripslashes($eventlistpage);
 
 if ($config == "config"){