Add support for "default" runtime

As gnatls does not support --RTS=default add a filter
to replace "default" with empty string which leads to
the same expected result.

Change-Id: I367f71f058a1473d935c8a2c615770138bdf1791
TN: T715-031

Author: fedor-rybin

src/gnatcoll-projects.adb

@@ -8098,20 +8098,26 @@ package body GNATCOLL.Projects is
       function Get_Value_Of_Runtime (Project : Project_Id) return String is
          Elem : constant Array_Element_Id := Value_Of
            (Get_String ("runtime"), Project.Decl.Arrays, Shared);
+
+         function Filter_Default (S : String) return String is
+           (if S = "default" then Unset else S);
+         --  Unlike gprconfig, gnatls cannot process --RTS=default, so we need
+         --  to replace it with empty value.
       begin
          if Elem = No_Array_Element then
             if Project.Extends = GPR.No_Project then
-               return Value_Of (Nil_Variable_Value, Unset);
+               return Filter_Default (Value_Of (Nil_Variable_Value, Unset));
             else
-               return Get_Value_Of_Runtime (Project.Extends);
+               return Filter_Default (Get_Value_Of_Runtime (Project.Extends));
             end if;
          else
-            return Value_Of
-               (Value_Of
-                    (Index    => Get_String ("ada"),
-                     In_Array => Elem,
-                     Shared   => Shared),
-              Unset);
+            return Filter_Default
+              (Value_Of
+                 (Value_Of
+                      (Index    => Get_String ("ada"),
+                       In_Array => Elem,
+                       Shared   => Shared),
+                  Unset));
          end if;
       end Get_Value_Of_Runtime;
 

testsuite/tests/projects/runtime_default/simple.gpr

@@ -0,0 +1,5 @@
+abstract project simple is
+
+   for Runtime ("Ada") use "default";
+
+end simple;

testsuite/tests/projects/runtime_default/test.adb

@@ -0,0 +1,29 @@
+with GNATCOLL.Projects; use GNATCOLL.Projects;
+with GNATCOLL.VFS;      use GNATCOLL.VFS;
+with GNATCOLL.Projects.Aux;
+
+with Test_Assert;
+
+function Test return Integer is
+   PT     : Project_Tree;
+   Env    : Project_Environment_Access;
+begin
+   Initialize (Env);
+   Env.Set_Automatic_Config_File;
+   PT.Load (Create ("simple.gpr"), Env);
+
+   declare
+      Predef_Sources : constant File_Array := Env.Predefined_Source_Files;
+   begin
+      Test_Assert.Assert
+        (Predef_Sources'Length > 0,
+         "check if runtime is found");
+   end;
+
+   GNATCOLL.Projects.Aux.Delete_All_Temp_Files (PT.Root_Project);
+
+   PT.Unload;
+   Free (Env);
+   return Test_Assert.Report;
+
+end Test;

testsuite/tests/projects/runtime_default/test.yaml

@@ -0,0 +1,5 @@
+description: >
+  Check that explicitly specified value "default"
+  for Ada runtime is properly processed.
+data:
+    - "simple.gpr"