diff --git a/lib/linguist/languages.yml b/lib/linguist/languages.yml
index 27aaa75e..442117a0 100755
--- a/lib/linguist/languages.yml
+++ b/lib/linguist/languages.yml
@@ -2024,6 +2024,7 @@ M4Sugar:
   filenames:
   - configure.ac
   tm_scope: none
+  ace_mode: text
 
 MAXScript:
   type: programming