diff --git a/ChangeLog b/ChangeLog
index 5a6df2cc04..9420a3355f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Mon Dec 22 17:07:31 2003  WATANABE Hirofumi  <eban@ruby-lang.org>
+
+	* configure.in (mingw): set isnan, finite and isinf to yes.
+
 Mon Dec 22 13:40:19 2003  NAKAMURA, Hiroshi  <nahi@ruby-lang.org>
 
 	* lib/soap/property.rb: passing block by reference.
diff --git a/configure.in b/configure.in
index 88be09ef9f..79950f0c21 100644
--- a/configure.in
+++ b/configure.in
@@ -300,6 +300,9 @@ mingw*)		LIBS="-lwsock32 $LIBS"
 		ac_cv_func_vsnprintf=yes
 		ac_cv_func_seekdir=yes
 		ac_cv_func_telldir=yes
+		ac_cv_func_isinf=yes
+		ac_cv_func_isnan=yes
+		ac_cv_func_finite=yes
 		ac_cv_lib_crypt_crypt=no
 		enable_pthread=no
 		;;