--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/ada/libgnat/a-envvar.ads	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,69 @@
+------------------------------------------------------------------------------
+--                                                                          --
+--                         GNAT RUN-TIME COMPONENTS                         --
+--                                                                          --
+--              A D A . E N V I R O N M E N T _ V A R I A B L E S           --
+--                                                                          --
+--                                 S p e c                                  --
+--                                                                          --
+-- This specification is derived from the Ada Reference Manual for use with --
+-- GNAT.  In accordance with the copyright of that document, you can freely --
+-- copy and modify this specification,  provided that if you redistribute a --
+-- modified version,  any changes that you have made are clearly indicated. --
+--                                                                          --
+------------------------------------------------------------------------------
+
+--  The implementation of this package is as defined in the Ada 2012 RM, but
+--  it is available in Ada 95 and Ada 2005 modes as well.
+
+package Ada.Environment_Variables is
+   pragma Preelaborate (Environment_Variables);
+
+   function Value (Name : String) return String;
+   --  If the external execution environment supports environment variables,
+   --  then Value returns the value of the environment variable with the given
+   --  name. If no environment variable with the given name exists, then
+   --  Constraint_Error is propagated. If the execution environment does not
+   --  support environment variables, then Program_Error is propagated.
+
+   function Value (Name : String; Default : String) return String;
+   --  If the external execution environment supports environment variables and
+   --  an environment variable with the given name currently exists, then Value
+   --  returns its value; otherwise, it returns Default.
+
+   function Exists (Name : String) return Boolean;
+   --  If the external execution environment supports environment variables and
+   --  an environment variable with the given name currently exists, then
+   --  Exists returns True; otherwise it returns False.
+
+   procedure Set (Name : String; Value : String);
+   --  If the external execution environment supports environment variables,
+   --  then Set first clears any existing environment variable with the given
+   --  name, and then defines a single new environment variable with the given
+   --  name and value. Otherwise Program_Error is propagated.
+   --
+   --  If implementation-defined circumstances prohibit the definition of an
+   --  environment variable with the given name and value, then exception
+   --  Constraint_Error is propagated.
+   --
+   --  It is implementation defined whether there exist values for which the
+   --  call Set (Name, Value) has the same effect as Clear (Name).
+
+   procedure Clear (Name : String);
+   --  If the external execution environment supports environment variables,
+   --  then Clear deletes all existing environment variables with the given
+   --  name. Otherwise Program_Error is propagated.
+
+   procedure Clear;
+   --  If the external execution environment supports environment variables,
+   --  then Clear deletes all existing environment variables. Otherwise
+   --  Program_Error is propagated.
+
+   procedure Iterate
+     (Process : not null access procedure (Name, Value : String));
+   --  If the external execution environment supports environment variables,
+   --  then Iterate calls the subprogram designated by Process for each
+   --  existing environment variable, passing the name and value of that
+   --  environment variable. Otherwise Program_Error is propagated.
+
+end Ada.Environment_Variables;