hg: build-infra/jdk8: * Add clean-<component> targets to top level Makefile.

[magnus.ihse.bursie at oracle.com]

Changeset: 6684b47d2af0
Author:    ihse
Date:      2012-08-15 12:10 +0200
URL:       http://hg.openjdk.java.net/build-infra/jdk8/rev/6684b47d2af0

* Add clean-<component> targets to top level Makefile.
* Improved make help target.
* Fixed missing or incorrect phony targets'
* Cleanup basic tools configuration.

! common/autoconf/basics.m4
! common/autoconf/generated-configure.sh
! common/makefiles/MakeHelpers.gmk
! common/makefiles/Makefile