diff --git a/ChangeLog b/ChangeLog
index 4a4d390008..e5f6a69929 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Fri Mar 29 10:24:10 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* include/ruby/io.h: undef POSIX compliants names on AIX, which are no
+	  longer needed.  patch suggested by edelsohn (David Edelsohn) in
+	  [ruby-core:53815].  [Bug #8174]
+
 Fri Mar 29 06:39:42 2013  Tanaka Akira  <akr@fsij.org>
 
 	* numeric.c (rb_num2ull): Cast double to unsigned LONG_LONG via
diff --git a/include/ruby/io.h b/include/ruby/io.h
index f341befefe..b5ea2e9c95 100644
--- a/include/ruby/io.h
+++ b/include/ruby/io.h
@@ -37,6 +37,8 @@ extern "C" {
 #  ifdef _AIX
 #    undef reqevents
 #    undef rtnevents
+#    undef events
+#    undef revents
 #  endif
 #  define RB_WAITFD_IN  POLLIN
 #  define RB_WAITFD_PRI POLLPRI