[BUGFIX] systemLocale related issues

* Improve the description of TYPO3_CONF_VARS[SYS][systemLocale] option
* Add a hint to this option in thumbs.php, when thumbnail generation
  fails with the file not being found.

Change-Id: I30b355604a1052f452ab4c15ae57724e92472a1b
Resolves: #21609
Releases: 4.6, 4.5
Reviewed-on: http://review.typo3.org/3715
Reviewed-by: Steffen Gebert
Tested-by: Steffen Gebert

t3lib/config_default.php

@@ -102,7 +102,7 @@
 		'enableDeprecationLog' => 'file',		// Commalist: Enables the logging of deprecated methods and functions. Default is 'file'. The following options are allowed: 'file': The log file will be written to typo3conf/deprecation_[hash-value].log  'devlog': The log will be written to the development log  'console': The log will be displayed in the Backend's Debug Console. The logging options can be combined by comma-separating them.
 		'maxFileNameLength' => 60,				// Integer: This is the maximum file name length. The value will be taken into account by basic file operations like renaming or creation of files and folders.
 		'UTF8filesystem' => FALSE,				// Boolean: If true and <a href="#BE-forceCharset">[BE][forceCharset]</a> is set to utf-8, then TYPO3 uses utf-8 to store file names. This allows for accented Latin letters as well as any other non-latin characters like Cyrillic and Chinese.
-		'systemLocale' => '',					// String: locale used for certain system related functions; for example escaping shell commands.
+		'systemLocale' => '',					// String: locale used for certain system related functions, e.g. escaping shell commands. If problems with filenames containing special characters occur, the value of this option is probably wrong. See <a href="http://php.net/manual/en/function.setlocale.php" target="_blank">setlocale()</a>.
 		'lockingMode' => 'simple',					// String: Define which locking mode is used to control requests to pages being generated. Can be one of either "disable" (no locking), "simple" (checks for file existance), "flock" (using PHPs <a href="http://php.net/flock" target="_blank">flock()</a> function), "semaphore" (using PHPs <a href="http://php.net/sem-acquire" target="_blank">sem_acquire()</a> function). Default is "disable".
 		'reverseProxyIP' => '',					// String: list of IP addresses. If TYPO3 is behind one or more (intransparent) reverese proxies the IP addresses must be added here.
 		'reverseProxyHeaderMultiValue' => 'none',		// String: "none","first","last": defines which values of a proxy header (eg HTTP_X_FORWARDED_FOR) to use, if more than one is found. "none" discards the value, "first" and "last" use the first/last of the values in the list.

t3lib/thumbs.php

@@ -182,8 +182,13 @@ function init()	{
 			$this->size = $size;
 			$this->mtime = $mtime;
 		} else {
+				// hide the path to the document root;
+			$publicFilename = substr($file, strlen(PATH_site));
 			throw new RuntimeException(
-				'TYPO3 Fatal Error: Image does not exist and/or MD5 checksum did not match.',
+				'TYPO3 Fatal Error: Image \'' . $publicFilename . '\' does not exist and/or MD5 checksum did not match. ' .
+					'If the target file exists and its file name contains special characters, the setting of ' .
+					'$TYPO3_CONF_VARS[SYS][systemLocale] might be wrong.'
+				,
 				1270853950
 			);
 		}