bug ID 32069: resetting an undefined env variable changes the errorlevel.

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@382808 13f79535-47bb-0310-9956-ffa450edef68

src/script/ant.bat

@@ -1,6 +1,6 @@
 @echo off
 
-REM  Copyright 2001,2004-2005 The Apache Software Foundation
+REM  Copyright 2001,2004-2006 The Apache Software Foundation
 REM
 REM  Licensed under the Apache License, Version 2.0 (the "License");
 REM  you may not use this file except in compliance with the License.
@@ -14,6 +14,12 @@ REM  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 REM  See the License for the specific language governing permissions and
 REM  limitations under the License.
 
+REM This is an inordinately troublesome piece of code, particularly because it
+REM tries to work on both Win9x and WinNT-based systems. If we could abandon '9x
+REM support, things would be much easier, but sadly, it is not yet time.
+REM Be cautious about editing this, and only add WinNT specific stuff in code that
+REM only runs on WinNT.
+
 if exist "%HOME%\antrc_pre.bat" call "%HOME%\antrc_pre.bat"
 
 if "%OS%"=="Windows_NT" @setlocal
@@ -149,7 +155,10 @@ set ANT_ERROR=%err100%%err10%%err1%
 for %%i in (1 10 100) do set err%%i=
 
 :end
+rem bug ID 32069: resetting an undefined env variable changes the errorlevel.
+set _JAVACMD=DUMMY_VAL
 set _JAVACMD=
+set ANT_CMD_LINE_ARGS=DUMMY_VAL
 set ANT_CMD_LINE_ARGS=
 
 rem Set the return code if we are not in NT.  We can only set