An aggregate project is now used to build XMLAda. The builder is now
gprbuild and the installation is conducted by gprinstall. This has
permitted a large clean-up of the makefile.
For N403-037.
git-svn-id: svn+ssh://svn.eu.adacore.com/Dev/trunk/xmlada@232625 936e1b1b-40f2-da11-902a-00137254ae57
