allow to customize temporary directory and to use syslog instead of temporary file

qrconfig.php

@@ -5,9 +5,16 @@
  * Config file, feel free to modify
  */
 
-    define('QR_CACHEABLE', true);                                                               // use cache - more disk reads but less CPU power, masks and format templates are stored there
+
+	if (!defined('QR_CACHEABLE')) {
+		define( 'QR_CACHEABLE', true );                                                               // use cache - more disk reads but less CPU power, masks and format templates are stored there
+	}
+	if (!defined('QR_CACHE_DIR')) {
     define('QR_CACHE_DIR', dirname(__FILE__).DIRECTORY_SEPARATOR.'cache'.DIRECTORY_SEPARATOR);  // used when QR_CACHEABLE === true
-    define('QR_LOG_DIR', dirname(__FILE__).DIRECTORY_SEPARATOR);                                // default error logs dir   
+	}
+	if (!defined('QR_LOG_DIR')) {
+		define( 'QR_LOG_DIR', dirname( __FILE__ ) . DIRECTORY_SEPARATOR );                                // default error logs dir
+	}
 
     define('QR_FIND_BEST_MASK', true);                                                          // if true, estimates best mask (spec. default, but extremally slow; set to false to significant performance boost but (propably) worst quality code
     define('QR_FIND_FROM_RANDOM', false);                                                       // if false, checks all masks available, otherwise value tells count of masks need to be checked, mask id are got randomly

qrencode.php

@@ -514,7 +514,7 @@ public function encodePNG($intext, $outfile = false,$saveandprint=false)
 
             } catch (Exception $e) {
 
-                QRtools::log($outfile, $e->getMessage());
+                QRtools::log($outfile, $e->getMessage() .' in '. $e->GetFile() . ':' . $e->GetLine());
 
             }
         }

qrtools.php

@@ -109,6 +109,9 @@ public static function log($outfile, $err)
                     }
                 }    
             }
+			if (defined('QR_LOG_SYSLOG') && QR_LOG_SYSLOG) {
+				syslog(LOG_ERR, '[QRTOOLS] '. $err);
+			}
         }
 
         //----------------------------------------------------------------------