diff --git a/ChangeLog b/ChangeLog
index 002706aa7ad137..a8601c2dfe3900 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,4 +1,7 @@
-Sat Sep  3 23:55:17 2011  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+Sat Sep  3 23:56:24 2011  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* configure.in (sizeof_struct_dirent_too_small): check if struct
+	  dirent.d_name is too small.
 
 	* configure.in (RUBY_MINGW32): take tool prefix from CC.
 
diff --git a/configure.in b/configure.in
index 616837d6ec5db4..14165a3c18b90e 100644
--- a/configure.in
+++ b/configure.in
@@ -933,15 +933,6 @@ dnl Checks for libraries.
 AS_CASE(["$target_os"],[*bsd*|dragonfly*],[],[ac_cv_func_daemon=no])
 
 AS_CASE(["$target_os"],
-[solaris*], [
-		AC_DEFINE(SIZEOF_STRUCT_DIRENT_TOO_SMALL, 1)
-		LIBS="-lm $LIBS"
-		],
-# GNU Hurd
-[gnu*], [
-		AC_DEFINE(SIZEOF_STRUCT_DIRENT_TOO_SMALL, 1)
-		LIBS="-lm $LIBS"
-		],
 [nextstep*], [	],
 [openstep*], [	],
 [rhapsody*], [	],
@@ -1734,6 +1725,38 @@ fi
 
 RUBY_CHECK_SIZEOF([struct stat.st_ino], [long "long long"], [], [@%:@include <sys/stat.h>])
 
+AC_CACHE_CHECK([whether struct dirent.d_name is too small], rb_cv_sizeof_struct_dirent_too_small,
+  [AC_COMPILE_IFELSE(
+    [AC_LANG_BOOL_COMPILE_TRY([AC_INCLUDES_DEFAULT([
+@%:@if defined _WIN32
+@%:@ error <<<struct direct in win32/dir.h has variable length d_name>>>
+@%:@elif defined HAVE_DIRENT_H
+@%:@ include <dirent.h>
+@%:@elif defined HAVE_DIRECT_H
+@%:@ include <direct.h>
+@%:@else
+@%:@ define dirent direct
+@%:@ if HAVE_SYS_NDIR_H
+@%:@  include <sys/ndir.h>
+@%:@ endif
+@%:@ if HAVE_SYS_DIR_H
+@%:@  include <sys/dir.h>
+@%:@ endif
+@%:@ if HAVE_NDIR_H
+@%:@  include <ndir.h>
+@%:@ endif
+@%:@endif
+@%:@include <stddef.h>
+@%:@define numberof(array) [(int)(sizeof(array) / sizeof((array)[0]))]
+struct dirent d;
+])],
+      [offsetof(struct dirent, [d_name[numberof(d.d_name)]]) - offsetof(struct dirent, d_name) < 256])],
+    [rb_cv_sizeof_struct_dirent_too_small=yes],
+    [rb_cv_sizeof_struct_dirent_too_small=no])])
+if test "$rb_cv_sizeof_struct_dirent_too_small" = yes; then
+  AC_DEFINE(SIZEOF_STRUCT_DIRENT_TOO_SMALL, 1)
+fi
+
 if test "$ac_cv_func_sysconf" = yes; then
   AC_DEFUN([RUBY_CHECK_SYSCONF], [dnl
   AC_CACHE_CHECK([whether _SC_$1 is supported], rb_cv_have_sc_[]m4_tolower($1),