Makes W3 Total Cache include each minified file's modtime in the filename, so that changes to css/js cause a new URL to be generated, allowing origin-pull CDN setups to work properly without manual invalidation.

minify-modtime.patch

--- a/w3-total-cache/lib/W3/Minify.php
+++ b/w3-total-cache/lib/W3/Minify.php
@@ -956,9 +956,10 @@ class W3_Minify {
         $replace = $this->_minify_path_replacements();
         $replaced = false;
         foreach ($optimized as $file) {
+            $mtime = filemtime(w3_get_document_root() . '/' . $file . '.' . $type);
             foreach($replace as $key => $path) {
                 if (strpos($file, $path) === 0) {
-                    $input[] =  str_replace($path, $key, $file);
+                    $input[] =  str_replace($path, $key, $file) . ':' . $mtime;
                     $replaced = true;
                     break;
                 }
@@ -966,7 +967,7 @@ class W3_Minify {
             if ($replaced)
                 $replaced = false;
             else
-                $input[] = $file;
+                $input[] = $file . ':' . $mtime;
         }

         $minify_filename = array();
@@ -1037,6 +1038,7 @@ class W3_Minify {
         $exploded = explode(',', $uncompressed);
         $replacements = $this->_minify_path_replacements();
         foreach($exploded as $file) {
+            list($file, $mtime) = explode(':', $file);
             if (!w3_is_url($file)) {
                 $prefix = substr($file,0,1);
                 $after_pre = substr($file, 1, 1);