2008-04-08  Vincent Celier  <celier@adacore.com>

	* clean.adb (Parse_Cmd_Line): Recognize switch --subdirs=
	(Usage): Add line for switch --subdirs=
	Add new switch -eL, to follow symbolic links when processing project
	files.

	* gnatcmd.adb: Process switches -eL and --subdirs=
	(Non_VMS_Usage): Output "gnaampcmd" instead of "gnat", and call
	Program_Name to get proper tool names when AAMP_On_Target is set.
	(Gnatcmd): Call Add_Default_Search_Dirs and Get_Target_Parameters to get
	AAMP_On_Target set properly for use of GNAAMP tools (this is needed by
	Osint.Program_Name).

	* gnatname.adb: (Scan_Args): Recognize switches -eL and --subdirs=
	(Usage): Add lines for switches -eL and --subdirs=

	* makeusg.adb: Add line for switch --subdirs=

	* prj.ads: 
	(Source_Data): New Boolean component Compiled, defaulted to True
	(Empty_File_Name: New global variable in private part, initialized in
	procedure Initialize.
	(Subdirs_Option): New constant string
	(Subdirs): New String_Ptr global variable
	(Language_Config): New component Include_Compatible_Languages
	(Project_Qualifier): New type for project qualifiers
	(Project_Data): New component Qualifier
	(Project_Configuration): New component Archive_Builder_Append_Option

	* prj-nmsc.adb (Get_Unit_Exceptions): When a unit is already in
	another imported project indicate the name of this imported project.
	(Check_File): When a unit is in two project files, indicate the project
	names and the paths of the source files for each project.
	(Add_Source): Set Compiled to False if compiler driver is empty. Only
	set object, dependency and switches file names if Compiled is True.
	(Process_Compiler): Allow the empty string for value of attribute Driver
	(Get_Directories): When Subdirs is not null and Object_Dir is not
	 specified, locate and create if necessary the actual object dir.
	(Locate_Directory): When Subdirs is not empty and Create is not the
	empty string, locate and create if necessary the actual directory
	as a subdirectory of directory Name.
	(Check_Library_Attributes.Check_Library): Allow a project where the only
	"sources" are header files of file based languages to be imported by
	library projects, in multi-language mode (gprbuild).
	(Check_Library_Attributes.Check_Library): In multi-language mode
	(gprbuild), allow a library project to import a project with no
	sources, even when this is not declared explicitly.
	(Check_If_Externally_Built): A virtual project extending an externally
	built project is also externally built.
	(Check_Library_Attributes): For a virtual project extending a library
	project, inherit the library directory.
	(Process_Project_Level_Array_Attributes): Process new attribute
	Inherit_Source_Path.
	For projects with specified qualifiers "standard", "library" or
	"abstract", check that the project conforms to the qualifier.
	(Process_Project_Level_Simple_Attributes): Process new attribute
	 Archive_Builder_Append_Option.

	* switch-m.adb: (Scan_Make_Switches): Process switch --subdirs=
	(Normalize_Compiler_Switches): Only keep compiler switches that are
	passed to gnat1 by the gcc driver and that are stored in the ALI file
	by gnat1.
	Do not take into account switc -save-temps

	* makegpr.adb (Compile_Link_With_Gnatmake): Transmit switch -eL if
	gprmake is called with -eL.
	(Scan_Arg): Recognize switch -eL
	(Usage): Add line for switch -eL

	* prj.adb (Initialize): Initialize Empty_File_Name
	(Project_Empty): New component Qualifier

	* prj-attr.ads, prj-attr.adb: New project level attribute
	Inherit_Source_Path.
	New project level attribute Archive_Builder_Append_Option

	* prj-dect.adb: Replace System.Strings by GNAT.Strings.

	* prj-ext.adb (Initialize_Project_Path): In Multi_Language mode, add
	<prefix>/lib/gnat in the project path, after <prefix>/share/gpr, for
	upward compatibility.

	* prj-part.adb (Project_Path_Name_Of.Try_Path): In high verbosity, put
	each Trying ..." on different lines.
	(Parse_Single_Project): Recognize project qualifiers. Fail in qualifier
	is "configuration" when not in configuration. Fail when in configuration
	when a specified qualifier is other than "configuration".

	* prj-proc.adb (Process_Declarative_Items): Link new elements of copied
	full associative array together.
	(Recursive_Process): Put the project qualifier in the project data
	
	* prj-tree.ads, prj-tree.adb: (Project_Qualifier_Of): New function
	(Set_Project_Qualifier_Of): New procedure

From-SVN: r134023