JOSM build broken

[stoecker]

The JAVACC changes break build:

BUILD FAILED
/home/stoecker/josm/core/build.xml:112: Problem: failed to create task or type javacc
Cause: the class org.apache.tools.ant.taskdefs.optional.javacc.JavaCC was not found.
        This looks like one of Ant's optional components.
Action: Check that the appropriate optional JAR exists in
        -/usr/share/ant/lib
        -/home/stoecker/.ant/lib
        -a directory added on the command line with the -lib argument

Do not panic, this is a common problem.
The commonest cause is a missing JAR.

This is not a bug; it is a configuration problem

        at org.apache.tools.ant.UnknownElement.getNotFoundException(UnknownElement.java:484)
        at org.apache.tools.ant.UnknownElement.makeObject(UnknownElement.java:416)
        at org.apache.tools.ant.UnknownElement.maybeConfigure(UnknownElement.java:160)
        at org.apache.tools.ant.Task.perform(Task.java:347)
        at org.apache.tools.ant.Target.execute(Target.java:357)
        at org.apache.tools.ant.Target.performTasks(Target.java:385)
        at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1337)
        at org.apache.tools.ant.Project.executeTarget(Project.java:1306)
        at org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExecutor.java:41)
        at org.apache.tools.ant.Project.executeTargets(Project.java:1189)
        at org.apache.tools.ant.Main.runBuild(Main.java:758)
        at org.apache.tools.ant.Main.startAnt(Main.java:217)
        at org.apache.tools.ant.launch.Launcher.run(Launcher.java:257)
        at org.apache.tools.ant.launch.Launcher.main(Launcher.java:104)

[stoecker]

In [4257/josm]:

fix #6603 - don't use optional javacc ant task