diff --git a/ChangeLog b/ChangeLog
index 1628d8afdc..a80ddc6b8f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sat Jan 12 16:12:46 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* win32/setup.mak (-runtime-): see msvcrt from link header on mswin
+	  instead of running testing executable file, for cross compiling.
+
 Sat Jan 12 08:58:47 2013  Aaron Patterson <aaron@tenderlovemaking.com>
 
 	* ext/psych/lib/psych/visitors/to_ruby.rb: merge key values that
diff --git a/win32/rtname.cmd b/win32/rtname.cmd
new file mode 100644
index 0000000000..1f410a02db
--- /dev/null
+++ b/win32/rtname.cmd
@@ -0,0 +1,18 @@
+@echo off
+set rt=
+set rtver=
+set osver=
+for /f "usebackq" %%I in (`dumpbin -dependents %1 ^| findstr -r -i "\<msvcr.*\.dll$"`) do set rt=%%~nI
+if "%rt%" == "" (
+    (echo %0: %1 is not linked to msvcrt) 1>&2
+    exit 1
+)
+for %%i in (a b c d e f g h i j k l m n o p q r s t u v w x y z) do @call set rt=%%rt:%%i=%%i%%
+if "%rt%" == "msvcrt" (
+    call set rtver=60
+) else (
+    call set rtver=%%rt:msvcr=%%
+    call set rt=msvcr%%rtver%%
+    call set osver=_%%rtver%%
+)
+for %%I in ("PLATFORM = $(TARGET_OS)%osver%" "RT = %rt%" "RT_VER = %rtver%") do @echo %%~I
diff --git a/win32/setup.mak b/win32/setup.mak
index 7c69334581..515271b85e 100644
--- a/win32/setup.mak
+++ b/win32/setup.mak
@@ -77,10 +77,10 @@ USE_RUBYGEMS = $(USE_RUBYGEMS)
 -system-vars64-: -osname64- -runtime-
 
 -osname32-: nul
-	@echo TARGET_OS = mswin32 >>$(MAKEFILE)
+	@echo TARGET_OS = mswin32>>$(MAKEFILE)
 
 -osname64-: nul
-	@echo TARGET_OS = mswin64 >>$(MAKEFILE)
+	@echo TARGET_OS = mswin64>>$(MAKEFILE)
 
 -osname-: nul
 	@echo !ifndef TARGET_OS>>$(MAKEFILE)
@@ -93,69 +93,12 @@ USE_RUBYGEMS = $(USE_RUBYGEMS)
 	@$(WIN32DIR:/=\)\rm.bat conftest.*
 
 -runtime-: nul
-	@$(CC) -MD <<rtname.c user32.lib -link > nul
-#include <windows.h>
-#include <memory.h>
-#include <string.h>
-#include <stddef.h>
+	@$(CC) -MD <<conftest.c user32.lib -link > nul
 #include <stdio.h>
-#include <stdlib.h>
-#ifndef MAXPATHLEN
-# define MAXPATHLEN 1024
-#endif
-
-int
-runtime_name()
-{
-    char libpath[MAXPATHLEN+1];
-    char *p, *base = NULL, *ver = NULL;
-    HMODULE msvcrt = NULL;
-    MEMORY_BASIC_INFORMATION m;
-
-    memset(&m, 0, sizeof(m));
-    if (VirtualQuery(stdin, &m, sizeof(m)) && m.State == MEM_COMMIT)
-	msvcrt = (HMODULE)m.AllocationBase;
-    GetModuleFileName(msvcrt, libpath, sizeof libpath);
-
-    libpath[sizeof(libpath) - 1] = '\0';
-    for (p = libpath; *p; p = CharNext(p)) {
-	if (*p == '\\') {
-	    base = ++p;
-	}
-    }
-    if (!base) return 0;
-    if (p = strchr(base, '.')) *p = '\0';
-    for (p = base; *p; p = CharNext(p)) {
-	if (!isascii(*p)) continue;
-	if (isupper(*p)) {
-	    *p = tolower(*p);
-	}
-	if (!isdigit(*p)) {
-	    ver = NULL;
-	} else if (!ver) {
-	    ver = p;
-	}
-    }
-    if (ver) {
-	printf("PLATFORM = $$(TARGET_OS)_%s\n", ver);
-    }
-    else {
-	printf("PLATFORM = $$(TARGET_OS)\n");
-	ver = "60";
-    }
-    printf("RT = %s\n", base);
-    printf("RT_VER = %s\n", ver);
-    return 1;
-}
-
-int main(int argc, char **argv)
-{
-    if (!runtime_name()) return EXIT_FAILURE;
-    return EXIT_SUCCESS;
-}
+int main(void) {FILE *volatile f = stdin; return 0;}
 <<
-	@.\rtname >>$(MAKEFILE)
-	@for %I in (rtname.*) do @del %I
+	@$(WIN32DIR:/=\)\rtname conftest.exe >>$(MAKEFILE)
+	@$(WIN32DIR:/=\)\rm.bat conftest.*
 
 -version-: nul
 	@$(APPEND)