[TASK] Inform user about possibly missing Ghostscript tools

Extend the error message for failing image tests to include a note
about possibly missing Ghostscript tools on the server.

Releases: master, 6.2
Resolves: #64677
Change-Id: I9dbc9e3b4afb8280c54d4ac87456f9272bdb0874
Reviewed-on: http://review.typo3.org/36487


Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Andreas Fernandez <andreas.fernandez@aspedia.de>
Tested-by: Andreas Fernandez <andreas.fernandez@aspedia.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>

typo3/sysext/install/Classes/Controller/Action/Tool/TestSetup.php

@@ -607,7 +607,7 @@ class TestSetup extends Action\AbstractAction {
 		$message->setMessage(
 			'ImageMagick / GraphicsMagick handling is enabled, but the execute'
 			. ' command returned an error. Please check your settings, especially'
-			. ' [\'GFX\'][\'im_path\'] and [\'GFX\'][\'im_path_lzw\'].'
+			. ' [\'GFX\'][\'im_path\'] and [\'GFX\'][\'im_path_lzw\'] and ensure Ghostscript is installed on your server.'
 		);
 		return $message;
 	}