diff --git a/sys-devel/bison/bison-2.4.3.bep b/sys-devel/bison/bison-2.4.3.bep
index 5630e1a92..b5c671042 100644
--- a/sys-devel/bison/bison-2.4.3.bep
+++ b/sys-devel/bison/bison-2.4.3.bep
@@ -8,7 +8,7 @@ DEPEND=""
 BUILD {
 	cd bison-2.4.3
 	prefix=$(finddir B_PACKAGE_LINKS_DIRECTORY)/bison-2.4.3
-	./configure --prefix=$prefix \
+	M4="m4" ./configure --prefix=$prefix \
 		--datarootdir=$prefix/data \
 		--sbindir=$prefix/bin \
 		--includedir=$prefix/develop/headers \