diff --git a/ChangeLog b/ChangeLog
index f762adf5b3..b0d95a202c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Wed Sep 28 09:14:16 2011  Nobuyoshi Nakada  <>
+
+	* configure.in (pthread_np.h): needs pthread.h to be included
+	  previously on OpenBSD.  a patch by George Koehler <xkernigh AT
+	  netscape.net> at [ruby-core:39752].  [Bug #5376]
+
 Wed Sep 28 04:41:35 2011  Ayumu AIZAWA  <ayumu.aizawa@gmail.com>
 
 	* test/psych/test_yamlstore.rb: use tmpdir for tmpfile.
diff --git a/configure.in b/configure.in
index 3af6aaa893..fff3a07eb0 100644
--- a/configure.in
+++ b/configure.in
@@ -1793,7 +1793,7 @@ if test x"$enable_pthread" = xyes; then
 	AC_DEFINE(_REENTRANT)
 	AC_DEFINE(_THREAD_SAFE)
 	AC_DEFINE(HAVE_LIBPTHREAD)
-	AC_CHECK_HEADERS(pthread_np.h)
+	AC_CHECK_HEADERS(pthread_np.h, [], [], [@%:@include <pthread.h>])
 	AS_CASE([$pthread_lib],
 	[c],    [],
 	[root], [],