Index: includes/common.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/common.inc,v
retrieving revision 1.611.2.25
diff -u -p -r1.611.2.25 common.inc
--- includes/common.inc	16 Sep 2009 17:29:09 -0000	1.611.2.25
+++ includes/common.inc	21 Feb 2010 02:06:27 -0000
@@ -1674,11 +1674,16 @@ function drupal_build_css_cache($types, 
     $data = implode('', $matches[0]) . $data;
 
     // Perform some safe CSS optimizations.
-    $data = preg_replace('<
-      \s*([@{}:;,]|\)\s|\s\()\s* |  # Remove whitespace around separators, but keep space around parentheses.
-      /\*([^*\\\\]|\*(?!/))+\*/ |   # Remove comments that are not CSS hacks.
-      [\n\r]                        # Remove line breaks.
-      >x', '\1', $data);
+    $comment     = '/\*[^*]*\*+(?:[^/*][^*]*\*+)*/'; // Regexp to match comment blocks.
+    $double_quot = '"[^"\\\\]*(?:\\\\.[^"\\\\]*)*"'; // Regexp to match double quoted strings.
+    $single_quot = "'[^'\\\\]*(?:\\\\.[^'\\\\]*)*'"; // Regexp to match single quoted strings.
+    $data = preg_replace_callback(
+      "<$double_quot|$single_quot|$comment>Sus",     // Match all comment blocks along with double/single quoted strings and feed them to _process_comment().
+      "_process_comment",
+      $data);
+    $data = preg_replace(
+      '<\s*([@{}:;,]|\)\s|\s\()\s*>S',               // Remove whitespace around separators, but keep space around parentheses.
+      '\1', $data);
 
     // Create the CSS file.
     file_save_data($data, $csspath .'/'. $filename, FILE_EXISTS_REPLACE);
@@ -1687,6 +1692,41 @@ function drupal_build_css_cache($types, 
 }
 
 /**
+ * Implements comment strip logic.
+ *
+ * This is the callback function for the preg_replace_callback() used in
+ * drupal_load_stylesheet_content(). Support for comment hacks is implemented here.
+ */
+function _process_comment($matches) {
+  static $keep_nextone = FALSE;
+  // Quoted string, keep it.
+  $start_char = substr($matches[0], 0, 1);
+  if ($start_char == "'" || $start_char == '"') {
+    return $matches[0];
+  }
+  // End of IE-Mac hack, keep it.
+  if ($keep_nextone) {
+    $keep_nextone = FALSE;
+    return $matches[0];
+  }
+  else {
+    switch (strrpos($matches[0], '\\')) {
+      // No backslash, strip it.
+      case FALSE :
+        return '';
+        break;
+      // Ends with \*/ so is a multi line IE-Mac hack, keep this and the next one.
+      case drupal_strlen($matches[0])-3 :
+        $keep_nextone = TRUE;
+        // Fall through to default case.
+      // Single line IE-Mac hack, keep this.
+      default :
+        return $matches[0];
+    }
+  }
+}
+
+/**
  * Delete all cached CSS files.
  */
 function drupal_clear_css_cache() {