[Ada] Use Dir_Seps everywhere to properly handle all directory speparators.

[Arnaud Charlet]

On Windows the directory separator can be / or \, in some cases this
was not properly handled. This patch fixes this issue.

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

2011-08-31  Pascal Obry  <o...@adacore.com>

        * a-direct.adb: Use Dir_Seps everywhere to properly handle all
        directory speparators.
        (Compose): Use Dir_Seps to handle both forms.
        (Create_Path): Use Dir_Seps instead of explicit check, no semantic
        changes.
        (Extension): Use Dir_Seps to handle both forms.


Index: a-direct.adb
===================================================================
--- a-direct.adb        (revision 178358)
+++ a-direct.adb        (working copy)
@@ -32,7 +32,7 @@
 with Ada.Calendar;               use Ada.Calendar;
 with Ada.Calendar.Formatting;    use Ada.Calendar.Formatting;
 with Ada.Directories.Validity;   use Ada.Directories.Validity;
-with Ada.Strings.Maps;
+with Ada.Strings.Maps;           use Ada; use Ada.Strings.Maps;
 with Ada.Strings.Fixed;
 with Ada.Strings.Unbounded;      use Ada.Strings.Unbounded;
 with Ada.Unchecked_Conversion;
@@ -61,8 +61,7 @@
    pragma Import (C, Dir_Separator, "__gnat_dir_separator");
    --  Running system default directory separator
 
-   Dir_Seps : constant Ada.Strings.Maps.Character_Set :=
-                Ada.Strings.Maps.To_Set ("/\");
+   Dir_Seps : constant Character_Set := Strings.Maps.To_Set ("/\");
    --  UNIX and DOS style directory separators
 
    Max_Path : Integer;
@@ -175,7 +174,7 @@
 
          --  Add a directory separator if needed
 
-         if Last /= 0 and then Result (Last) /= Dir_Separator then
+         if Last /= 0 and then not Is_In (Result (Last), Dir_Seps) then
             Last := Last + 1;
             Result (Last) := Dir_Separator;
          end if;
@@ -457,17 +456,13 @@
 
             --  Look for the end of an intermediate directory
 
-            if New_Dir (J) /= Dir_Separator and then
-               New_Dir (J) /= '/'
-            then
+            if not Is_In (New_Dir (J), Dir_Seps) then
                Last := J;
 
             --  We have found a new intermediate directory each time we find
             --  a first directory separator.
 
-            elsif New_Dir (J - 1) /= Dir_Separator and then
-                  New_Dir (J - 1) /= '/'
-            then
+            elsif not Is_In (New_Dir (J - 1), Dir_Seps) then
 
                --  No need to create the directory if it already exists
 
@@ -664,7 +659,7 @@
             --  If a directory separator is found before a dot, there is no
             --  extension.
 
-            if Name (Pos) = Dir_Separator then
+            if Is_In (Name (Pos), Dir_Seps) then
                return Empty_String;
 
             elsif Name (Pos) = '.' then