diff --git a/ChangeLog b/ChangeLog
index 81a0e22c5e..de714b3ab1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,4 +1,6 @@
-Tue Apr  1 11:36:19 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+Tue Apr  1 14:43:38 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* configure.in: get rid of empty expansion.
 
 	* configure.in: _setjmp is available but _longjmp is not on mingw.
 
diff --git a/configure.in b/configure.in
index 87eb4301fa..e5866ed9bd 100644
--- a/configure.in
+++ b/configure.in
@@ -749,7 +749,7 @@ elif test "$ac_cv_func_sigsetjmp" = yes; then
 else
     setjmp_prefix=
 fi
-if test $setjmp_prefix = sig; then
+if test x$setjmp_prefix = xsig; then
     setjmp_sigmask=yes
 else
     unset setjmp_sigmask