Add another fix for media query boundaries

Evaluate the actual queries against each other.
We probably need to implement a better test here!

extend.cpp

@@ -1679,9 +1679,17 @@ namespace Sass {
         for (ExtensionPair ext : entries) {
           // check if both selectors have the same media block parent
           if (ext.first->media_block() == pComplexSelector->media_block()) continue;
+          To_String to_string(&ctx);
+          if (ext.first->media_block() && ext.first->media_block()->media_queries() &&
+              pComplexSelector->media_block() && pComplexSelector->media_block()->media_queries())
+          {
+            string query_left(ext.first->media_block()->media_queries()->perform(&to_string));
+            string query_right(pComplexSelector->media_block()->media_queries()->perform(&to_string));
+            if (query_left == query_right) continue;
+          }
+
           // fail if one goes across media block boundaries
           stringstream err;
-          To_String to_string(&ctx);
           string cwd(Sass::File::get_cwd());
           ParserState pstate(ext.second->pstate());
           string rel_path(Sass::File::resolve_relative_path(pstate.path, cwd, cwd));
@@ -1709,7 +1717,7 @@ namespace Sass {
           break;
         }
       }
-      if (!pExtendSelector->is_optional()) {
+      if (!pExtendSelector || !pExtendSelector->is_optional()) {
         string sel2(pExtendSelector ? pExtendSelector->perform(&to_string) : "[unknown]");
         err << "\"" << sel1 << "\" failed to @extend \"" << sel2 << "\"\n";
         err << "The selector \"" << sel2 << "\" was not found.\n";

parser.cpp

@@ -728,7 +728,7 @@ namespace Sass {
     bool semicolon = false;
     Selector_Lookahead lookahead_result;
     Block* block = new (ctx.mem) Block(pstate);
-    lex< spaces_and_comments >();
+    // lex< zero_plus < alternatives < space, line_comment > > >();
     // JMA - ensure that a block containing only block_comments is parsed
     while (lex< block_comment >()) {
       bool is_important = lexed.begin[2] == '!';