diff --git a/Build.sh b/Build.sh
index c211bfb..5cbf1ba 100644
--- a/Build.sh
+++ b/Build.sh
@@ -1,5 +1,5 @@
 #!/bin/sh
-srcversion='$MirOS: src/bin/mksh/Build.sh,v 1.486 2011/08/26 10:20:28 tg Exp $'
+srcversion='$MirOS: src/bin/mksh/Build.sh,v 1.487 2011/08/26 10:24:51 tg Exp $'
 #-
 # Copyright (c) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011
 #	Thorsten Glaser <tg@mirbsd.org>
@@ -379,6 +379,10 @@ else
 fi
 
 test x"$TARGET_OS" = x"" && TARGET_OS=`uname -s 2>/dev/null || uname`
+if test x"$TARGET_OS" = x""; then
+	echo "$me: Set TARGET_OS, your uname is broken!" >&2
+	exit 1
+fi
 oswarn=
 ccpc=-Wc,
 ccpl=-Wl,
@@ -1165,7 +1169,7 @@ else
 		#define EXTERN
 		#define MKSH_INCLUDES_ONLY
 		#include "sh.h"
-		__RCSID("$MirOS: src/bin/mksh/Build.sh,v 1.486 2011/08/26 10:20:28 tg Exp $");
+		__RCSID("$MirOS: src/bin/mksh/Build.sh,v 1.487 2011/08/26 10:24:51 tg Exp $");
 		int main(void) { printf("Hello, World!\n"); return (0); }
 EOF
 	case $cm in