diff --git a/.gitignore b/.gitignore
index 5492535..c38ee77 100644
--- a/.gitignore
+++ b/.gitignore
@@ -19,6 +19,7 @@
 Makefile.in
 ylwrap
 m4/*
+!m4/ax_*.m4
 
 # Generated by `./configure`
 config.h