prj-attr.adb: New attributes in package Clean: Artifacts_In_Exec_Dir, Artifacts_In_Ob...

prj-attr.adb: New attributes in package Clean: Artifacts_In_Exec_Dir, Artifacts_In_Object_Dir.

2013-10-14  Vincent Celier  <celier@adacore.com>

	* prj-attr.adb: New attributes in package Clean:
	Artifacts_In_Exec_Dir, Artifacts_In_Object_Dir.
	* prj-nmsc.adb (Process_Clean (Attributes)): New
	procedure to process attributes Artifacts_In_Exec_Dir and
	Artifacts_In_Object_Dir in package Clean.
	* prj.ads (Project_Configuration): New components
	Artifacts_In_Exec_Dir and Artifacts_In_Object_Dir.
	* snames.ads-tmpl: New standard names Artifacts_In_Exec_Dir and
	Artifacts_In_Object_Dir used only by gprclean.

From-SVN: r203529