MDL-52336 core: patch PHPExcel for PHP7 compatibility

lib/phpexcel/PHPExcel/Shared/PCLZip/pclzip.lib.php

@@ -212,7 +212,7 @@ class PclZip
     //     Note that no real action is taken, if the archive does not exist it is not
     //     created. Use create() for that.
     // --------------------------------------------------------------------------------
-    public function PclZip($p_zipname)
+    public function __construct($p_zipname)
     {
 
         // ----- Tests the zlib

lib/phpexcel/PHPExcel/Worksheet/AutoFilter/Column.php

@@ -393,9 +393,9 @@ class PHPExcel_Worksheet_AutoFilter_Column
                 //    The columns array of PHPExcel_Worksheet_AutoFilter objects
                 $this->$key = array();
                 foreach ($value as $k => $v) {
-                    $this->$key[$k] = clone $v;
+                    $this->{$key[$k]} = clone $v;
                     // attach the new cloned Rule to this new cloned Autofilter Cloned object
-                    $this->$key[$k]->setParent($this);
+                    $this->{$key[$k]}->setParent($this);
                 }
             } else {
                 $this->$key = $value;

lib/phpexcel/readme_moodle.txt

@@ -25,6 +25,7 @@ Changes:
    - PHPExcel/Writer/Excel5/Worksheet.php
    - PHPExcel/Writer/Excel5/Xf.php
    lib/excellib.class.php has been updated so that only 2007 excel spreadsheets will be produced.
+ * MDL-52336 patch for PHP7 compatibility, after upgrade make sure that these changes are included and remove this line