[Ada] Remove an obsolete variant of Adjust_Name_Case used only by SPARK

[Pierre-Marie de Rodat]

GNATprove no longer calls an obsolete variant of Adjust_Name_Case that
uses a global buffer.

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

gcc/ada/

        * errout.ads (Adjust_Name_Case): Remove obsolete and now unused
        variant.
        * errout.adb (Adjust_Name_Case): Likewise; fix variant that uses
        a custom buffer to also use it for names in Standard_Location.
diff --git a/gcc/ada/errout.adb b/gcc/ada/errout.adb
--- a/gcc/ada/errout.adb
+++ b/gcc/ada/errout.adb
@@ -3402,7 +3402,7 @@ package body Errout is
          --  For standard locations, always use mixed case
 
          if Loc <= No_Location then
-            Set_Casing (Mixed_Case);
+            Set_Casing (Buf, Mixed_Case);
 
          else
             --  Determine if the reference we are dealing with corresponds to
@@ -3440,11 +3440,6 @@ package body Errout is
       end;
    end Adjust_Name_Case;
 
-   procedure Adjust_Name_Case (Loc : Source_Ptr) is
-   begin
-      Adjust_Name_Case (Global_Name_Buffer, Loc);
-   end Adjust_Name_Case;
-
    ---------------------------
    -- Set_Identifier_Casing --
    ---------------------------


diff --git a/gcc/ada/errout.ads b/gcc/ada/errout.ads
--- a/gcc/ada/errout.ads
+++ b/gcc/ada/errout.ads
@@ -985,10 +985,6 @@ package Errout is
    --  the name at that source location, we copy the casing from the source,
    --  otherwise we set appropriate default casing.
 
-   procedure Adjust_Name_Case (Loc : Source_Ptr);
-   --  Uses Buf => Global_Name_Buffer. There are no calls to this in the
-   --  compiler, but it is called in SPARK 2014.
-
    procedure Set_Identifier_Casing
      (Identifier_Name : System.Address;
       File_Name       : System.Address);