Fixes #5260 Check for json support during setup

setup/class_setupStep_Checks.inc

@@ -95,6 +95,14 @@ class Step_Checks extends setupStep
     $M = TRUE;
     $basic_checks[] = array('NAME' => $N , 'DESC' => $D , 'RESULT' => $R , 'SOLUTION' => $S , 'MUST' => $M );
 
+    /* Check for json support */
+    $N = msgPool::checkingFor('json');
+    $D = _('FusionDirectory requires this module to encode variables for javascript use.');
+    $S = msgPool::installPhpModule('json');
+    $R = is_callable('json_encode');
+    $M = TRUE;
+    $basic_checks[] = array('NAME' => $N , 'DESC' => $D , 'RESULT' => $R , 'SOLUTION' => $S , 'MUST' => $M );
+
     /* Check for iconv */
     $N = msgPool::checkingFor("iconv");
     $D = _("FusionDirectory requires this module for the samba integration.");