Bug 37197 Basepath for relative pathes in JAR-exporter
The basepath for the JAR-exporter is the eclipse-install-directory. I prefer it to be the root of the project (the description is saved in), so that relative pathes end inside the project. Now: <jardesc> <jar path="workspace/projectdir/jar.jar"/> Desired: <jardesc> <jar path="jar.jar"/> Reason: To make the jardesc-files portable for shared projects
org.eclipse.jdt.ui/ui/org/eclipse/jdt/ui/jarpackager/JarPackageData.java
* Set if compilation units with warnings are exported.
	 * 
	 * @param exportWarnings <code>true</code> if CUs with warnings should be exported
	 */
	public void setExportWarnings(boolean exportWarnings) {
		fExportWarnings= exportWarnings;
	}
	
	/**
	 * Answers if a build should be performed before exporting files.
	 * This flag is only considered if auto-build is off.
	 * 
	 * @return a boolean telling if a build should be performed
	 */
	public boolean isBuildingIfNeeded() {
		return fBuildIfNeeded;
	}
	
	/**
	 * Set if a build should be performed before exporting files.
	 * This flag is only considered if auto-build is off.
	 * 
	 * @param a boolean telling if a build should be performed
	 */
	public void setBuildIfNeeded(boolean fBuildIfNeeded) {
		this.fBuildIfNeeded= fBuildIfNeeded;
	}
	
	
	/**