diff --git a/ChangeLog b/ChangeLog
index cae5031c52..a7550481e8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,4 +1,7 @@
-Sat Nov  6 07:30:07 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+Sat Nov  6 07:33:08 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* configure.in (rb_cv_export_prefix): check for prefixed
+	  underscore of exported symbols
 
 	* tool/rbinstall.rb (bin-comm): prepend prolog shell script if
 	  necessary.
diff --git a/configure.in b/configure.in
index e0f8f6444f..43962e026c 100644
--- a/configure.in
+++ b/configure.in
@@ -2344,6 +2344,13 @@ AC_SUBST(INSTALLDOC)
 if test "$rb_with_pthread" = "yes"; then
     THREAD_MODEL=pthread
 fi
+AC_CACHE_CHECK([for prefixed underscore of exported symbols], rb_cv_export_prefix, [
+    AC_TRY_COMPILE([extern void conftest_exported(void) {}], [], [
+	rb_cv_export_prefix=`$NM conftest.$ac_objext |
+			     sed -n ['s/.*\(_\)conftest_exported.*/\1/p']`
+	],
+	[rb_cv_export_prefix=''])
+])
 MINIDLNOBJ=dmydln.o
 AS_CASE(["$target_os"],
     [linux*], [
@@ -2409,7 +2416,8 @@ AS_CASE(["$target_os"],
 		LIBRUBY_SO='$(RUBY_SO_NAME)'.dll
 		LIBRUBY_DLDFLAGS="${LIBRUBY_DLDFLAGS}"' $(RUBYDEF)'
 	    fi
-	    EXPORT_PREFIX=' '
+	    test -z "$rb_cv_export_prefix" && rb_cv_export_prefix=' '
+	    EXPORT_PREFIX="$rb_cv_export_prefix"
 	    DLDFLAGS="${DLDFLAGS}"' $(DEFFILE)'
 	    AC_LIBOBJ([win32])
 	    COMMON_LIBS=m