diff --git a/evolution.spec b/evolution.spec
index df17cc8..4384285 100644
--- a/evolution.spec
+++ b/evolution.spec
@@ -398,7 +398,7 @@ CFLAGS="$CFLAGS \
 
 # Rerun the GNU Autotools since we patched some of the input files.
 # Disable portability checking to keep automake 1.10 quiet.
-autoreconf --warnings=no-portability
+autoreconf --force --warnings=no-portability
 
 %configure \
   --disable-scrollkeeper \