diff --git a/ChangeLog b/ChangeLog
index 20be1d4a47..06ef729f5d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,9 +1,14 @@
+Mon Jun  6 15:10:17 2011  NAKAMURA Usaku  <usa@ruby-lang.org>
+
+	* include/ruby/{defines,missing}.h (rb_infinity, rb_nan): move from
+	  defines.h to missing.h.  (couldn't use RUBY_EXTERN there.)
+
 Mon Jun  6 14:35:48 2011  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* test/rdoc/test_rdoc_markup_pre_process.rb (TestRDocMarkupPreProcess#
 	  {test_include_file,test_include_file_encoding_incompatible}): no
-	  need to write such workaround.  don't hide the bug of ruby (and the
-	  bug is already fixed)
+	  need to write such workaround.  don't hide the bug of ruby. (and the
+	  bug is already fixed.)
 
 Mon Jun  6 14:11:11 2011  NAKAMURA Usaku  <usa@ruby-lang.org>
 
diff --git a/include/ruby/defines.h b/include/ruby/defines.h
index c9d6db2f6b..ea38dc3689 100644
--- a/include/ruby/defines.h
+++ b/include/ruby/defines.h
@@ -133,22 +133,6 @@ void xfree(void*);
 #define PRIxBDIGIT_DBL PRI_BDIGIT_DBL_PREFIX"x"
 #define PRIXBDIGIT_DBL PRI_BDIGIT_DBL_PREFIX"X"
 
-#ifdef INFINITY
-# define HAVE_INFINITY
-#else
-/** @internal */
-RUBY_EXTERN const unsigned char rb_infinity[];
-# define INFINITY (*(float *)rb_infinity)
-#endif
-
-#ifdef NAN
-# define HAVE_NAN
-#else
-/** @internal */
-RUBY_EXTERN const unsigned char rb_nan[];
-# define NAN (*(float *)rb_nan)
-#endif
-
 #ifdef __CYGWIN__
 #undef _WIN32
 #endif
diff --git a/include/ruby/missing.h b/include/ruby/missing.h
index 1a1aa958ac..ac0a5c9dc0 100644
--- a/include/ruby/missing.h
+++ b/include/ruby/missing.h
@@ -119,6 +119,22 @@ RUBY_EXTERN double lgamma_r(double, int *);
 RUBY_EXTERN double cbrt(double);
 #endif
 
+#ifdef INFINITY
+# define HAVE_INFINITY
+#else
+/** @internal */
+RUBY_EXTERN const unsigned char rb_infinity[];
+# define INFINITY (*(float *)rb_infinity)
+#endif
+
+#ifdef NAN
+# define HAVE_NAN
+#else
+/** @internal */
+RUBY_EXTERN const unsigned char rb_nan[];
+# define NAN (*(float *)rb_nan)
+#endif
+
 #ifndef isinf
 # ifndef HAVE_ISINF
 #  if defined(HAVE_FINITE) && defined(HAVE_ISNAN)