diff --git a/gcc/ada/ChangeLog b/gcc/ada/ChangeLog
index cb38dab12f0856fc1bfa000a5a22918eed7f3fe5..6c975b45034f3a561e5a319edd2b96c454b57c8e 100644
--- a/gcc/ada/ChangeLog
+++ b/gcc/ada/ChangeLog
@@ -1,3 +1,9 @@
+2009-09-16  Thomas Quinot  <quinot@adacore.com>
+
+	* s-oscons-tmplt.c (Target_OS, Target_Name): New constants.
+	* g-expect.adb (Set_Up_Child_Communications): Use
+	System.OS_Constants.Target_OS to determine whether running on Windows.
+
 2009-09-14  Richard Henderson  <rth@redhat.com>
 
 	* gcc-interface/trans.c (Pragma_to_gnu): Use build5 for ASM_EXPR.
diff --git a/gcc/ada/g-expect.adb b/gcc/ada/g-expect.adb
index 02bc6cf8a79c2abc5dc4fffcea5179d4043e450f..a67696a649d5d73ad27a53e6982b72bd5c6fc2a8 100644
--- a/gcc/ada/g-expect.adb
+++ b/gcc/ada/g-expect.adb
@@ -31,8 +31,9 @@
 --                                                                          --
 ------------------------------------------------------------------------------
 
-with System;       use System;
-with Ada.Calendar; use Ada.Calendar;
+with System;              use System;
+with System.OS_Constants; use System.OS_Constants;
+with Ada.Calendar;        use Ada.Calendar;
 
 with GNAT.IO;
 with GNAT.OS_Lib;  use GNAT.OS_Lib;
@@ -1195,15 +1196,14 @@ package body GNAT.Expect is
       pragma Warnings (Off, Pipe2);
       pragma Warnings (Off, Pipe3);
 
-      On_Windows : constant Boolean := Directory_Separator = '\';
-      --  This is ugly, we need a better way of doing this test ???
-
       Input  : File_Descriptor;
       Output : File_Descriptor;
       Error  : File_Descriptor;
 
+      No_Fork_On_Target : constant Boolean := Target_OS = Windows;
+
    begin
-      if On_Windows then
+      if No_Fork_On_Target then
 
          --  Since Windows does not have a separate fork/exec, we need to
          --  perform the following actions:
diff --git a/gcc/ada/s-oscons-tmplt.c b/gcc/ada/s-oscons-tmplt.c
index c4218c2ab78b4c2dee473f724be3ed4818a6a50b..a2ae16e35c3082112ee56fd670da116be8a81782 100644
--- a/gcc/ada/s-oscons-tmplt.c
+++ b/gcc/ada/s-oscons-tmplt.c
@@ -175,6 +175,9 @@ int counter = 0;
 
 #endif
 
+#define STR(x) STR1(x)
+#define STR1(x) #x
+
 #ifdef __MINGW32__
 unsigned int _CRT_fmode = _O_BINARY;
 #endif
@@ -216,6 +219,25 @@ package System.OS_Constants is
  **  General constants (all platforms)
  **/
 
+/*
+
+   -----------------------------
+   -- Platform identification --
+   -----------------------------
+
+*/
+TXT("   Target_Name : constant String := " STR(TARGET) ";")
+/*
+   type Target_OS_Type is (Windows, VMS, Other_OS);
+*/
+#if defined (__MINGW32__)
+# define TARGET_OS Windows
+#elif defined (__VMS)
+# define TARGET_OS VMS
+#else
+# define TARGET_OS Other_OS
+#endif
+TXT("   Target_OS : constant Target_OS_Type := " STR(TARGET_OS) ";")
 /*
 
    -------------------