diff --git a/configure.ac b/configure.ac
index 912019c..b67262f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,5 +1,5 @@
 AC_PREREQ(2.59)
-AC_INIT(tang, 2)
+AC_INIT(tang, 3)
 AC_CANONICAL_SYSTEM
 AC_PROG_CC_C99
 AC_PROG_SED