2004-10-26  Vincent Celier  <celier@gnat.com>

	* prj-nmsc.adb (Language_Independent_Check): Do not forbid virtual
	extension of library projects.

	* prj-part.adb: If env var ADA_PROJECT_PATH is not defined, project
	path defaults to ".:<prefix>/lib/gnat".
	(Parse): For an extending all project, allow direct import of a project
	that is virtually extended.

	* prj-proc.adb (Imported_Or_Extended_Project_From): If a project with
	the specified name is directly imported, return its ID. Otherwise, if
	an extension of this project is imported, return the ID of the
	extension.

From-SVN: r89662