diff --git a/doc/doxygen.conf b/doc/doxygen.conf
index 2df72fe45..291d3f9df 100644
--- a/doc/doxygen.conf
+++ b/doc/doxygen.conf
@@ -1,3 +1,5 @@
+# -*-sh-*-
+
 # Doxyfile 1.8.1.1
 
 # This file describes the settings to be used by the documentation system