[Ada] Revert recent changes in the generation of deps in ali files

Following the discovery of regressions in GPRbuild, this reverts both
r263100 and r264608:

2019-01-08  Justin Squirek  <squirek@adacore.com>

	Revert:

	2018-07-31  Justin Squirek  <squirek@adacore.com>

	gcc/ada/

		* lib-writ.adb (Write_With_Lines): Modfiy the generation
		of dependencies within ali files so that source unit
		bodies are properly listed even if said bodies are
		missing.  Perform legacy behavior in GNATprove mode.
		* lib-writ.ads: Modify documentation to reflect current
		behavior.

	and:

	2018-09-26  Justin Squirek  <squirek@adacore.com>

	gcc/ada/

		* lib-writ.adb, lib-writ.ads (Write_With_Lines): Add
		documentation and an extra conditional check for RCI
		units so that generated ali files will list the spec
		only instead of a body when a body is not found.

From-SVN: r267680

gcc/ada/ChangeLog

+2019-01-08  Justin Squirek  <squirek@adacore.com>
+
+	Revert:
+
+	2018-07-31  Justin Squirek  <squirek@adacore.com>
+
+	gcc/ada/
+
+		* lib-writ.adb (Write_With_Lines): Modfiy the generation
+		of dependencies within ali files so that source unit
+		bodies are properly listed even if said bodies are
+		missing.  Perform legacy behavior in GNATprove mode.
+		* lib-writ.ads: Modify documentation to reflect current
+		behavior.
+
+	and:
+
+	2018-09-26  Justin Squirek  <squirek@adacore.com>
+
+	gcc/ada/
+
+		* lib-writ.adb, lib-writ.ads (Write_With_Lines): Add
+		documentation and an extra conditional check for RCI
+		units so that generated ali files will list the spec
+		only instead of a body when a body is not found.
+
 2019-01-04  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* gnatvsn.ads: Bump copyright year.

gcc/ada/lib-writ.adb

@@ -953,42 +953,17 @@ package body Lib.Writ is
                Write_Info_Tab (25);
 
                if Is_Spec_Name (Uname) then
+                  Body_Fname :=
+                    Get_File_Name
+                      (Uname    => Get_Body_Name (Uname),
+                       Subunit  => False,
+                       May_Fail => True);
 
-                  --  In GNATprove mode we must write the spec of a unit which
-                  --  requires a body if that body is not found. This will
-                  --  allow partial analysis on incomplete sources. Also, in
-                  --  the case of a unit that is a remote call interface, the
-                  --  bodies of packages may not exist but still may form a
-                  --  valid program - so we handle that here as well.
-
-                  if GNATprove_Mode
-                    or else Is_Remote_Call_Interface (Cunit_Entity (Unum))
-                  then
-                     Body_Fname :=
-                       Get_File_Name
-                         (Uname    => Get_Body_Name (Uname),
-                          Subunit  => False,
-                          May_Fail => True);
-
-                     Body_Index := Get_Unit_Index (Get_Body_Name (Uname));
-
-                     if Body_Fname = No_File then
-                        Body_Fname := Get_File_Name (Uname, Subunit => False);
-                        Body_Index := Get_Unit_Index (Uname);
-                     end if;
-
-                  --  In the normal path we don't allow failure in fetching the
-                  --  name of the desired body unit so that it may be properly
-                  --  referenced in the output ali - even if it is missing.
-
-                  else
-                     Body_Fname :=
-                       Get_File_Name
-                         (Uname    => Get_Body_Name (Uname),
-                          Subunit  => False,
-                          May_Fail => False);
+                  Body_Index := Get_Unit_Index (Get_Body_Name (Uname));
 
-                     Body_Index := Get_Unit_Index (Get_Body_Name (Uname));
+                  if Body_Fname = No_File then
+                     Body_Fname := Get_File_Name (Uname, Subunit => False);
+                     Body_Index := Get_Unit_Index (Uname);
                   end if;
                else
                   Body_Fname := Get_File_Name (Uname, Subunit => False);

gcc/ada/lib-writ.ads

@@ -629,14 +629,13 @@ package Lib.Writ is
    --      by the current unit. One Z line is present for each unit that is
    --      only implicitly withed by the current unit. The first parameter is
    --      the unit name in internal format. The second parameter is the file
-   --      name of the body unit on which the current compilation unit depends,
-   --      except when in GNATprove mode or when the unit is a remote call
-   --      interface. In these cases, when packages that require a body have
-   --      no associated source file, the file name of the spec is used instead
-   --      to allow partial analysis of incomplete sources. The third parameter
-   --      is the file name of the library information file that contains the
-   --      results of compiling this unit. The optional modifiers are used as
-   --      follows:
+   --      name of the file that must be compiled to compile this unit. It is
+   --      usually the file for the body, except for packages which have no
+   --      body. For units that need a body, if the source file for the body
+   --      cannot be found, the file name of the spec is used instead. The
+   --      third parameter is the file name of the library information file
+   --      that contains the results of compiling this unit. The optional
+   --      modifiers are used as follows:
 
    --        E   pragma Elaborate applies to this unit