handle no javac on command line better.

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@277467 13f79535-47bb-0310-9956-ffa450edef68

bootstrap.bat

@@ -63,6 +63,8 @@ echo ... Compiling Ant Classes
 
 "%JAVAC%" %BOOTJAVAC_OPTS% -d %CLASSDIR% %TOOLS%\bzip2\*.java %TOOLS%\tar\*.java %TOOLS%\zip\*.java %TOOLS%\ant\*.java %TOOLS%\ant\types\*.java %TOOLS%\ant\taskdefs\*.java %TOOLS%\ant\util\regexp\RegexpMatcher.java %TOOLS%\ant\util\regexp\RegexpMatcherFactory.java %TOOLS%\ant\taskdefs\condition\*.java %TOOLS%\ant\taskdefs\compilers\*.java 
 
+if ERRORLEVEL 1 goto mainend
+
 echo.
 echo ... Copying Required Files