this.symbols.remove( argument + ":defined" );
	private void processUndefine(String argument, StringList lines, String className ) 	throws BuildException	{		if (argument.equals("true")) {			throw new BuildException( className + " line " + (lines.getCurrentIndex() +1) 					+ ": found invalid #undefine directive: the symbol [true] cannot be defined.");		}		Object symbol = this.temporarySymbols.remove( argument );		this.symbols.remove( argument );		if (symbol == null) {			this.temporaryVariables.remove( argument );			this.variables.remove( argument );		}	}