diff --git a/Makefile.local b/Makefile.local
index c3fc7c5c..361b2a02 100644
--- a/Makefile.local
+++ b/Makefile.local
@@ -1,3 +1,5 @@
+# -*- makefile -*-
+
 # Here's the (hopefully simple) versioning scheme.
 #
 # Releases of notmuch have a two-digit version (0.1, 0.2, etc.). We
diff --git a/compat/Makefile.local b/compat/Makefile.local
index 17b45140..81e6c707 100644
--- a/compat/Makefile.local
+++ b/compat/Makefile.local
@@ -1,3 +1,5 @@
+# -*- makefile -*-
+
 dir := compat
 extra_cflags += -I$(dir)
 
diff --git a/emacs/Makefile.local b/emacs/Makefile.local
index bda3997a..ee402e00 100644
--- a/emacs/Makefile.local
+++ b/emacs/Makefile.local
@@ -1,3 +1,5 @@
+# -*- makefile -*-
+
 dir := emacs
 emacs_sources := $(dir)/notmuch.el
 
diff --git a/lib/Makefile.local b/lib/Makefile.local
index f5d61883..5f493ee9 100644
--- a/lib/Makefile.local
+++ b/lib/Makefile.local
@@ -1,3 +1,5 @@
+# -*- makefile -*-
+
 # The major version of the library interface. This will control the soname.
 # As such, this number must be incremented for any incompatible change to
 # the library interface, (such as the deletion of an API or a major