diff --git a/configure-libafs.in b/configure-libafs.ac
similarity index 100%
rename from configure-libafs.in
rename to configure-libafs.ac
diff --git a/configure.in b/configure.ac
similarity index 100%
rename from configure.in
rename to configure.ac
diff --git a/regen.sh b/regen.sh
index 7121a839cd..397b80e6e6 100755
--- a/regen.sh
+++ b/regen.sh
@@ -28,7 +28,7 @@ fi
 echo "Running autoconf"
 autoconf
 echo "Running autoconf for configure-libafs"
-autoconf configure-libafs.in > configure-libafs
+autoconf configure-libafs.ac > configure-libafs
 chmod +x configure-libafs
 echo "Running autoheader"
 autoheader