diff --git a/package/m4/Config.in b/package/m4/Config.in
index 56b2859fc..dee2d833f 100644
--- a/package/m4/Config.in
+++ b/package/m4/Config.in
@@ -1,6 +1,8 @@
 config BR2_PACKAGE_M4
 	bool "m4"
 	depends on BR2_USE_WCHAR
+	# uses fork()
+	depends on BR2_USE_MMU
 	help
 	  An implementation of the traditional Unix macro processor.