diff --git a/binutils/ChangeLog b/binutils/ChangeLog
index 7a7edab7ed..47e5fa85db 100644
--- a/binutils/ChangeLog
+++ b/binutils/ChangeLog
@@ -1,3 +1,7 @@
+2017-10-10  Tom Tromey  <tom@tromey.com>
+
+	* dwarf-mode.el: Set lexical-binding.
+
 2017-10-10  Tom Tromey  <tom@tromey.com>
 
 	* dwarf-mode.el (dwarf-mode-map): New defvar.
diff --git a/binutils/dwarf-mode.el b/binutils/dwarf-mode.el
index c2c01ee745..dc6834826e 100644
--- a/binutils/dwarf-mode.el
+++ b/binutils/dwarf-mode.el
@@ -1,4 +1,4 @@
-;;; dwarf-mode.el --- Browser for DWARF information.
+;;; dwarf-mode.el --- Browser for DWARF information. -*-lexical-binding:t-*-
 
 ;; Version: 1.3