[Ada] Clean up -gnat2012 messages

Index: par-ch4.adb
===================================================================
--- par-ch4.adb	(revision 163054)
+++ par-ch4.adb	(working copy)
@@ -2670,7 +2670,7 @@  package body Ch4 is
    begin
       if Ada_Version < Ada_12 then
          Error_Msg_SC ("|case expression is an Ada 2012 feature");
-         Error_Msg_SC ("\|use -gnat12 switch to compile this unit");
+         Error_Msg_SC ("\|unit must be compiled with -gnat2012 switch");
       end if;
 
       Scan; -- past CASE
@@ -2761,7 +2761,7 @@  package body Ch4 is
 
       if Token = Tok_If and then Ada_Version < Ada_12 then
          Error_Msg_SC ("|conditional expression is an Ada 2012 feature");
-         Error_Msg_SC ("\|use -gnat12 switch to compile this unit");
+         Error_Msg_SC ("\|unit must be compiled with -gnat2012 switch");
       end if;
 
       Scan; -- past IF or ELSIF
@@ -2844,7 +2844,7 @@  package body Ch4 is
       if Token = Tok_Vertical_Bar then
          if Ada_Version < Ada_12 then
             Error_Msg_SC ("set notation is an Ada 2012 feature");
-            Error_Msg_SC ("\|use -gnat12 switch to compile this unit");
+            Error_Msg_SC ("\|unit must be compiled with -gnat2012 switch");
          end if;
 
          Set_Alternatives (N, New_List (Alt));
Index: errout.ads
===================================================================
--- errout.ads	(revision 163054)
+++ errout.ads	(working copy)
@@ -376,8 +376,14 @@  package Errout is
    Gname5 : aliased constant String := "gnat05";
    Vname5 : aliased constant String := "05";
 
-   Gname6 : aliased constant String := "gnat12";
-   Vname6 : aliased constant String := "12";
+   Gname6 : aliased constant String := "gnat2005";
+   Vname6 : aliased constant String := "2005";
+
+   Gname7 : aliased constant String := "gnat12";
+   Vname7 : aliased constant String := "12";
+
+   Gname8 : aliased constant String := "gnat2012";
+   Vname8 : aliased constant String := "2012";
 
    type Cstring_Ptr is access constant String;
 
@@ -387,7 +393,9 @@  package Errout is
                Gname3'Access,
                Gname4'Access,
                Gname5'Access,
-               Gname6'Access);
+               Gname6'Access,
+               Gname7'Access,
+               Gname8'Access);
 
    Vnames : array (Nat range <>) of Cstring_Ptr :=
               (Vname1'Access,
@@ -395,7 +403,9 @@  package Errout is
                Vname3'Access,
                Vname4'Access,
                Vname5'Access,
-               Vname6'Access);
+               Vname6'Access,
+               Vname7'Access,
+               Vname8'Access);
 
    -----------------------------------------------------
    -- Global Values Used for Error Message Insertions --
Index: vms_data.ads
===================================================================
--- vms_data.ads	(revision 163054)
+++ vms_data.ads	(working copy)
@@ -1229,6 +1229,13 @@  package VMS_Data is
    --
    --   Allows GNAT to recognize the full range of Ada 2005 constructs.
 
+   S_GCC_Ada_2005 : aliased constant S := "/2005 "                         &
+                                             "-gnat2005";
+   --        /05 (D)
+   --
+   --   Allows GNAT to recognize the full range of Ada 2005 constructs.
+   --   Equivalent to /05 (/2005 is the preferred usage).
+
    S_GCC_Ada_12 : aliased constant S := "/12 "                             &
                                              "-gnat12";
    --        /05 (D)
@@ -1236,6 +1243,14 @@  package VMS_Data is
    --   Allows GNAT to recognize all implemented proposed Ada 2012
    --   extensions. See features file for list of implemented features.
 
+   S_GCC_Ada_2012 : aliased constant S := "/2012 "                         &
+                                             "-gnat2012";
+   --        /05 (D)
+   --
+   --   Allows GNAT to recognize all implemented proposed Ada 2012
+   --   extensions. See features file for list of implemented features.
+   --   Equivalent to /12 (/2012 is the preferred usage).
+
    S_GCC_Add     : aliased constant S := "/ADD_PROJECT_SEARCH_DIR=*"       &
                                             "-aP*";
    --        /ADD_PROJECT_SEARCH_PATH=(directory[,...])
@@ -3443,6 +3458,9 @@  package VMS_Data is
                     (S_GCC_Ada_83  'Access,
                      S_GCC_Ada_95  'Access,
                      S_GCC_Ada_05  'Access,
+                     S_GCC_Ada_2005'Access,
+                     S_GCC_Ada_12  'Access,
+                     S_GCC_Ada_2012'Access,
                      S_GCC_Add     'Access,
                      S_GCC_Asm     'Access,
                      S_GCC_AValid  'Access,