Smarter exception handling.

install.php

@@ -43,26 +43,26 @@ $basePath = '/vufind';
 try {
     $opts = new Getopt(
         array(
-        'use-defaults' => 
+        'use-defaults' =>
            'Use VuFind Defaults to Configure (ignores any other arguments passed)',
-        'overridedir=s' => 
+        'overridedir=s' =>
            "Where would you like to store your local settings? [{$baseDir}/local]",
-        'module-name=s' => 
+        'module-name=s' =>
            'What module name would you like to use? Use disabled, to not use',
-        'basepath=s' => 
+        'basepath=s' =>
            'What base path should be used in VuFind\'s URL? [/vufind]',
-        'multisite-w' => 
+        'multisite-w' =>
            'Specify we are going to setup a multisite. Options: directory and host',
-        'hostname=s' => 
+        'hostname=s' =>
             'Specify the hostname for the VuFind Site, When multisite=host',
         'non-interactive' =>
             'Use settings if provided via arguments, otherwise use defaults',
       )
     );
-
     $opts->parse();
 } catch (Exception $e) {
-    echo $e->getUsageMessage();
+    echo is_callable([$e, 'getUsageMessage'])
+        ? $e->getUsageMessage() : $e->getMessage() . "\n";
     exit;
 }