diff --git a/ChangeLog b/ChangeLog
index 8fda9460f0..28a3e08176 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,4 +1,9 @@
-Sun Jun 30 10:57:13 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+Sun Jun 30 10:58:47 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* dln.h (DLN_FIND_EXTRA_ARG, DLN_FIND_EXTRA_ARG_DECL): allow extra
+	  arguments to dln_find_{exe,file}_r().
+
+	* dln_find.c (dln_find_exe_r, dln_find_file_r): add extract arguments.
 
 	* process.c (EXPORT_STR, EXPORT_DUP): convert to default process
 	  encoding if defined.
diff --git a/dln.h b/dln.h
index 762517113f..d98b2607e2 100644
--- a/dln.h
+++ b/dln.h
@@ -30,8 +30,15 @@
 
 RUBY_SYMBOL_EXPORT_BEGIN
 
-char *dln_find_exe_r(const char*,const char*,char*,size_t);
-char *dln_find_file_r(const char*,const char*,char*,size_t);
+#ifndef DLN_FIND_EXTRA_ARG
+#define DLN_FIND_EXTRA_ARG
+#endif
+#ifndef DLN_FIND_EXTRA_ARG_DECL
+#define DLN_FIND_EXTRA_ARG_DECL
+#endif
+
+char *dln_find_exe_r(const char*,const char*,char*,size_t DLN_FIND_EXTRA_ARG_DECL);
+char *dln_find_file_r(const char*,const char*,char*,size_t DLN_FIND_EXTRA_ARG_DECL);
 
 #ifdef USE_DLN_A_OUT
 extern char *dln_argv0;
diff --git a/dln_find.c b/dln_find.c
index 3160235b74..f41ceb051d 100644
--- a/dln_find.c
+++ b/dln_find.c
@@ -63,10 +63,12 @@ char *dln_argv0;
 char *getenv();
 #endif
 
-static char *dln_find_1(const char *fname, const char *path, char *buf, size_t size, int exe_flag);
+static char *dln_find_1(const char *fname, const char *path, char *buf, size_t size, int exe_flag
+			DLN_FIND_EXTRA_ARG_DECL);
 
 char *
-dln_find_exe_r(const char *fname, const char *path, char *buf, size_t size)
+dln_find_exe_r(const char *fname, const char *path, char *buf, size_t size
+	       DLN_FIND_EXTRA_ARG_DECL)
 {
     char *envpath = 0;
 
@@ -82,21 +84,23 @@ dln_find_exe_r(const char *fname, const char *path, char *buf, size_t size)
 	path = "/usr/local/bin:/usr/ucb:/usr/bin:/bin:.";
 #endif
     }
-    buf = dln_find_1(fname, path, buf, size, 1);
+    buf = dln_find_1(fname, path, buf, size, 1 DLN_FIND_EXTRA_ARG);
     if (envpath) free(envpath);
     return buf;
 }
 
 char *
-dln_find_file_r(const char *fname, const char *path, char *buf, size_t size)
+dln_find_file_r(const char *fname, const char *path, char *buf, size_t size
+		DLN_FIND_EXTRA_ARG_DECL)
 {
     if (!path) path = ".";
-    return dln_find_1(fname, path, buf, size, 0);
+    return dln_find_1(fname, path, buf, size, 0 DLN_FIND_EXTRA_ARG);
 }
 
 static char *
 dln_find_1(const char *fname, const char *path, char *fbuf, size_t size,
-	   int exe_flag /* non 0 if looking for executable. */)
+	   int exe_flag /* non 0 if looking for executable. */
+	   DLN_FIND_EXTRA_ARG_DECL)
 {
     register const char *dp;
     register const char *ep;