Trigger adjacent_posts_rel_link() from wp_head only for single post pages to avoid unnecessary queries. see #10867

git-svn-id: http://svn.automattic.com/wordpress/trunk@14019 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/link-template.php

@@ -1094,6 +1094,19 @@ function adjacent_posts_rel_link($title = '%title', $in_same_cat = false, $exclu
 	echo get_adjacent_post_rel_link($title, $in_same_cat, $excluded_categories = '', false);
 }
 
+/**
+ * Display relational links for the posts adjacent to the current post for single post pages.
+ *
+ * This is meant to be attached to actions like 'wp_head'.  Do not call this directly in plugins or theme templates.
+ * @since 3.0.0
+ *
+ */
+function adjacent_posts_rel_link_wp_head() {
+	if ( !is_singular() || is_attachment() )
+		return;
+	adjacent_posts_rel_link();
+}
+
 /**
  * Display relational link for the next post adjacent to the current post.
  *