diff --git a/polymake.spec b/polymake.spec
index fc855b8..d016a63 100644
--- a/polymake.spec
+++ b/polymake.spec
@@ -80,6 +80,7 @@ objects, and other objects.
 %autosetup -p1
 
 %build
+free
 # Not AC.
 ./configure --prefix="%_prefix" --libdir="%_libdir" \
 	--libexecdir="%_libdir/%name-%version" --without-native \