[Ada] Add unit file name for subunits in Alfa section of ALI file

[Arnaud Charlet <charlet at adacore dot com>]

The unit file name is needed when processing Alfa references from subunits,
in the formal verification backend of GNAT. Thus, add the unit file name
information for subunits in the line of the Alfa section that gives the
subunit file name.

Tested on x86_64-pc-linux-gnu, committed on trunk

2012-03-15  Yannick Moy  <moy@adacore.com>

	* alfa.ads Update the decription of ALI sections.
	(Alfa_File_Record): Add a component Unit_File_Name to store the
	unit file name for subunits.
	* get_alfa.adb, put_alfa.adb Adapt to the possible presence of
	a unit file name.
	* lib-xref-alfa.adb (Add_Alfa_File): For subunits, retrieve the
	file name of the unit.

Attachment: difs
Description: Text document