From f1121cf8c28370696e642b1a67f886a7b42fd50c Mon Sep 17 00:00:00 2001
From: Mathieu David <mathieudavid@mathieudavid.org>
Date: Sun, 4 Jun 2017 20:47:34 +0200
Subject: [PATCH] fix build failure

---
 src/bin/mdbook.rs | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/bin/mdbook.rs b/src/bin/mdbook.rs
index 78387ba1..416aa081 100644
--- a/src/bin/mdbook.rs
+++ b/src/bin/mdbook.rs
@@ -358,7 +358,10 @@ fn trigger_on_change<F>(book: &mut MDBook, closure: F) -> ()
     };
 
     // Add the theme directory to the watcher
-    watcher.watch(book.get_theme_path(), Recursive).unwrap_or_default();
+    if let Some(t) = book.get_theme_path() {
+        watcher.watch(t, Recursive).unwrap_or_default();
+    }
+
 
     // Add the book.{json,toml} file to the watcher if it exists, because it's not
     // located in the source directory