[Ada] Project_Dir should not modify the case of its path name

[Arnaud Charlet]

This patch ensures that when project'Project_Dir is used, the path will
not be modified, even on platforms where the file names are case
insensitive, such as Windows.

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

2012-10-04  Vincent Celier  <cel...@adacore.com>

        * prj-proc.adb (Process_Package_Declaration): Use project
        directory display path name as the value of 'Project_Dir.


Index: prj-proc.adb
===================================================================
--- prj-proc.adb        (revision 192066)
+++ prj-proc.adb        (working copy)
@@ -1588,7 +1588,7 @@
                   Add_Attributes
                     (Project,
                      Project.Name,
-                     Name_Id (Project.Directory.Name),
+                     Name_Id (Project.Directory.Display_Name),
                      Shared,
                      Shared.Packages.Table (New_Pkg).Decl,
                      First_Attribute_Of