diff --git a/m4 b/m4
index dee05804e..1b6f2ed72 160000
--- a/m4
+++ b/m4
@@ -1 +1 @@
-Subproject commit dee05804e3b9f2892d23eb5e0d4222e4ff32f2ef
+Subproject commit 1b6f2ed72d2365e0e9c3919321acabe57020e74c