diff --git a/recipe/build.sh b/recipe/build.sh
index 5fe27be..8d92b95 100644
--- a/recipe/build.sh
+++ b/recipe/build.sh
@@ -7,6 +7,10 @@ fi
 # Get an updated config.sub and config.guess
 cp $BUILD_PREFIX/share/gnuconfig/config.* .
 
+# set path to M4 to work around autoconf bug
+# see https://github.com/conda-forge/autoconf-feedstock/issues/41
+export M4=$(which m4)
+
 autoconf
 
 ./configure \