diff --git a/ChangeLog b/ChangeLog
index 8ec9546f73..556892ae74 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Thu Sep 24 00:00:17 2015  Rei Odaira  <Rei.Odaira@gmail.com>
+
+	* complex.c: ruby/config.h must be included before math.h
+	  because it defines _LARGE_FILES on AIX and _LARGE_FILES
+	  must be defined before sys/types.h is included from math.h.
+	  [Bug #11483]
+
 Wed Sep 23 22:22:38 2015  Zachary Scott  <zzak@ruby-lang.org>
 
         * ext/openssl/ossl_pkcs12*: Remove svn commit id macro
diff --git a/complex.c b/complex.c
index beaf6713a1..e3c20139f2 100644
--- a/complex.c
+++ b/complex.c
@@ -5,6 +5,7 @@
   which is written in ruby.
 */
 
+#include "ruby/config.h"
 #if defined _MSC_VER
 /* Microsoft Visual C does not define M_PI and others by default */
 # define _USE_MATH_DEFINES 1